I'm getting either a 10 gallon tank or a 50 gallon tank going to be community. But right now my betta's in a 1.5 gallon tank, that's a huge upgrade. so how can I do it?
Like you would when adding any fish to a new aquarium. I'd suggest a fish LESS cycle which can take 6-8 wks unless you get seeded materials from somewhere. You'd need ammonia & a liquid water test kit. If you choose fish IN cycling you'll still need the liquid water test kit because you'll need to test daily & do LOTS of water changes to keep your fish safe. Whenever you add a fish you will need to properly acclimate it before putting him into the tank. My 10g tank took 8 weeks with fish IN cycling & my 46g took 5-6 wks fish IN with 50% water changes every other day & a couple of times 2 in one day on the 10g.
Find someone with a clean healthy fish tank that's been set up for 6m+ and put a small piece of filter in their filter. Leave for a week, then take it and put it in your filter. It will jump start your cycle, makes it much easier. Good luck, the first cycled tank is always the hardest!
What do you mean? Are you going to do a fish in cycle? I put the entire tank together with gravel, deco's, plants (real & fake), filter, water & last Betta. Not sure if that's what you're asking or not. Definitely should have the substrate in first, you can add plants & deco's any time.