Newbie336, welcome to Tropical Fish Keeping forum.
We have a fish profiles section, click on the second tab from the left in the blue bar at the top to go there. Freshwater fish are divided into the categories like Characins (the tetra, hatchetfish and pencilfish are all here), Catfish (corys and other bottom fish, except loaches), Cyprinids (rasbora, danio, barb, loaches), etc. Read through and find things you like. Each profile has advice on minimum tank size [for that spcies understand, the more species you have the bigger the tank needed], numbers of each species (shoaling fish must be in groups), compatible fish, etc.
Your water parameters are important, both hardness and pH. Some fish have specific needs, others are adaptable to some degree. This is also mentioned in the profiles.
The tank also has to cycle; read up on that here: A Beginner's Guide to the Freshwater Aquarium Cycle