welcome aboard
40 G fowlr
If I do it for myself this is how I do it
get some southdown sand, play sand (quartz base, not silicat base) about 60 lbl , wash it then put in the tank
get 40 lbl of live sand , or arag-alive sand (20 lbls bag) or Bio-active sand also 20 lbls bag add on top play sand. With about 100 lbl of sand will take about 3-4 inches in your 40 G tank.
water , use RO/DI water if you could obtain a RO/DI unit, if not get RO water from Walmat at 35-40 cents / gallon
Liverock, order online about 45-50 lbls uncured live rock (cheaper and useful to cycle your new tank) after/during the cycling you can add another 10-15 lbls liverock from LFS (hand pick benifit)
Protien skimmer for 40 G, I would get Red Sea Primz or Sea Clone 100
Lighting system is not very critical for fish only tank but I would get 2 x 55 w PC or 2 x 30 W NO (1 actinic and 1 10000 K)
good luck