This is a basic, largely spoiler-free guide I've created to help players navigate the game, in case someone forgot what to do or missed something.
Players start the game in Dr. Thorne's Laboratory. They can explore most of the lab immediately, but it's generally best to go straight to Dr. Thorne's office to get a starter, as he gives a pair of Running Shoes afterwards that makes exploring quicker.
After leaving the lab, players head south down Route 4, then east down Route 8 to reach Norfon Village.
To progress past Norfon Village, players have to take part in a tournament. They're required to have at least 3 Pokémon to enter, so they're required to catch at least one, in addition to their starter and the gift Vulpix north of the arena.
Actually winning battles in the tournament is unnecessary, but winning all four will allow players to choose a prize.
After the tournament players head south down Route 10 to reach Mariville Town, where they take on the first gym, led by Max and his Grass types.
After obtaining the first badge, players get on board a boat by talking to the captain standing on the dock. They'll have to get a boat ticket from the nearby ticket building first, but it's paid for by the Pokémon League, so they just need to pick it up.
On board the boat, they'll have to complete the "Triple Challenge" hosted by the captain and crew, culminating in a battle against Captain Lang and his Water types.
After completing the Triple Challenge, players will then rest in the bed in their cabin.
Once rested, they'll have to win a few multi-battles alongside Callie, before winding up on Penrith Isle.
To leave Penrith Isle, players have to talk with the champion. She'll tell them to find the ship's captain and bring him to her, at which point she'll teach them Cut, allowing them to descend into the nearby sinkhole, past the building at the bottom, and into the cave behind it.
By going through the cave, they'll find themselves trapped in an abandoned laboratory. To escape, they'll need to find a Fuel Cell, and use the Dowsing Machine to find a backup generator to put the Fuel Cell in. Once that's been done, they can use the lab's teleporters to escape to Dr. Thorne's Laboratory, and then teleport to the Nightwell Laboratory.
Nightwell's Gym Leader isn't at the gym when they first arrive in the city, so they first have to head past the Department Store and through the West Tunnel to Nightwell Port. After the scene they see there, they can challenge Gym Leader Aurora and her Fairy types.
After obtaining the second badge, players go to Nightwell City's police department to give a statement about the boat to Regina of the International Police.
After giving their statement, players battle Callie next to the Department Store, before heading up through the North Tunnel to Route I, and then northwest to Araceli Town.
In Araceli Town, players take a trolley to either Central City or Reselda City, but are stopped by an Alpha Absol appearing on the tracks. After battling the Absol, players are left stranded in Central City.
Players can find Solaire talking to Fierte's governor, Kendrick. Once Solaire leaves, players battle Kendrick, and can then follow Solaire to a cave on the beach.
In the cave, players find a door. An uncatchable Alpha Dronurk emerges and attacks when players try to enter, which players have to defeat. Solaire also attacks after Dronurk's defeat, but players only have to survive a few turns against her.
After being invited into the Central Sanctuary, players can receive a quest from the Dronurk to fetch Zach from the League HQ. After heading there and talking to the man at the front desk, players can return to Dronurk to complete the quest.
After meeting Zach, players can find Xander and Tessa outside the Central City Gym. Once they leave, players can enter the gym and sign up for tournaments.
Once the player has finished the quest with Zach and joined a tournament (or told the Gym Guide they weren't interested), the trolley will begin running again, allowing players to leave the city and either go to Reselda City or back to Araceli Town.
In Reselda City, players can simply enter the gym, solve the puzzle, and challenge Tessa and her Electric types. In Araceli Town, players must enter the gym and take the Cable Car up to Mt. Yarost Shoulder before they can take on the puzzle and challenge Xander and his Flying types.
Upon entering the BP shop to the west of the Central City gym, players will meet Mika.
After meeting Mika, players can return to her and Aurora's house in Nightwell City and speak with her to accept a quest, which also allows them to enter the Nightwell Elementary School.
In the school, players can enter a tournament hosted by Mika focused around Double Battles using rental Pokémon. By winning the tournament, players can earn the right to challenge Mika and her Normal types.
(Mika's team is slightly stronger than Xander or Tessa's Gym 3 team. Also, the battle against her is always a Double Battle, like in her tournament. Players do get to use their own Pokémon to battle her instead of rentals, though.)
After obtaining the third badge, players go to whichever of the two gyms they haven't beaten yet, but along the way, they wind up in the Yarostian Range.
While making their way through the Yarostian Range and Yarostian Caverns, they find themselves in the Yarost Laboratory.
After an unsettling battle, learning Strength, and maybe a few more battles for good measure, players have a conference call with someone calling themselves Eclipse, who lets them escape the laboratory through a hole in the wall on floor BF2.
While continuing to make their way through the Yarostian Range, players stumble across the Solarite Order, battling a few Zealots before having to battle one of their leaders, Lieutenant Nolan.
After defeating Nolan, Regina arrives and brings players to the base of the mountains, where they meet Elise, and are given a bicycle so they're allowed on the Cycling Roads.
With the map opened back up, players can make their way to Araceli Town and Reselda City again, and challenge whichever Gym Leader they haven't beaten yet. (Tessa's Electric types and Xander's Flying types will all be higher level if battled as the fourth Gym Leader than if they were battled as the third.)
After obtaining the fourth badge, players are told to attend a meeting at the Pokémon League HQ in Central City.
At the end of the meeting, they're given a Jetpack and learn Fly, and be told to travel south from Reselda City to reach their next gym.
However, the route leading south from Reselda City is blocked by an inconveniently placed ocean liner that definitely wasn't put there to block players from reaching areas that haven't been created yet or to mark the end of the game's current content.