I am also relatively new to aquariums but the way i started my 30 gal
Fill tank with all decorations and gravel
Fill tank with water
Install heater and allow it to acclimate before turning it on ( overnight should do )
Then turn on heater and let it reach safe temp.
All along allowing filter to run
Chemical wise I believe any water conditioner sold at most pet stores is a safe bet to remove chlorine and make water safe
After about 2 days what I did was just sprinkle some fish food in the tank and the cycling will begin
The cycling can easily take 2 weeks during which time u will need to test for nitrites nitrates and ammonia
I would not skimp on the test kit I purchased the API Master kit which was a bit pricey but gave u all u need in one box
When all tests read zero the cycle is complete
Then u can start to introduce fish (slowly) maybe 3 or 4 hardy inexpensive fish like plattys
Leave them in there for about a month testing quite often.
There u go , that's how I did it with great results. I'm sure many others will have other helpfull advice. But this way worked for me.