The first mod you'll be working with is Tetra. Tetra is essentially the Tinkers Construct of this mod pack, allowing you to make custom tools. The first step is to create two wooden hammers and an extra crafting table. Once you have the hammer, right click the hammer on the extra crafting table. At this point, you can also make your first set of normal tools (up to stone toolset) and grab some iron. Note: The holosphere you obtain is important, as it gives you info regarding tools and materials that work well, so don't lose it.
Once you have some iron, we're going to upgrade our hammers. Hammer levels are important as they allow us to build and upgrade every other tool. Certain ores you want to use will need a high-level hammer, so that's what we're going to upgrade first. A level 3 (Iron) hammer should suffice for the time being. The workbench may look scary, but there's not that much to worry about right now. Just focus on what happens in the video.
Now that we have high level hammers, we can start upgrading our other tools. If you still have the same stone tool set, you can use it to upgrade. From this point on, it is encouraged that you keep your tools, as they will now have custom modifiers and more. When upgrading a tool, there will be an integrity bar. If that is full, you can't upgrade with anything else. You can increase this by adding certain upgrades, like adding string as a binding.
From this point on, you can upgrade and explore Tetra as much as you want. If you need additional information on Tetra, please refer to other Youtube videos as there are other useful items and mechanics in the mod. Some important factors are settling and arrested parts. What those mean is that, when a part is settled, it will add durability and other useful buffs to your tool. Settling is done by just using the tool normally (mining, chopping, etc.). When a part is arrested, it means it can't settle. This probably occurs when you've used a pretty good material already, so a buff would make it broken. To see the progress on a part, place the tool in the workbench, click on the part, and on the left of the small menu, click the first tab.