food for exped? ideas - start here: https://lotsafreshair.com/2014/03/10/easy-hiking-food-for-overnight-trips-thats-lightweight-too/
A great breakfast for the trail - up and go are a no : https://australianhiker.com.au/advice/tropical-overnight-oats-hiking-style/ and https://www.ahikersfriend.com/post/5-overnight-oats-recipes-for-the-hiking-trail
layering your clothing from One Planet:
waterproofing basics:
how to load your pack
watch this guy get hypothermia so you never do :)
Outdoor stores to check out:
Kathmandu tends to be fine for cheaper clothing (and some times sleeping bags).
For proper gear - ($$ investments that you will care for) - quality inflatable mattress or hiking rucksack, proper footwear etc - it is worth travelling beyond 2077 to Chatswood or the CBD:
Chatswood - Mountain Equipment are at72 Archer Street. Good people.
City - IMHO definitely worth a trip to Kent Street (just behind Town Hall station)
Take some time to shop around, the following stores tend to employ good people and have a great range:
3 excellent stores very close to each other: Paddy Pallin, Mountain Equipment, & Macpac - with Trek and Travel a little further North (across Druitt Street)
Be careful not to accidentally buy a Travel Pack :) Back lengths can be fixed or adjustable. We typically loan out packs with a 65 Litre capacity.