Getting a 20 gal long soon. I wanted to do an Amazon biotope. Any help and advice would be great.

I'm getting a 20 gal long soon and wanting to do an Amazon biotope. I have a few questions.

I know almost everything I need, including a heater, filter, air pump, thermometer. ph reader, water treating stuff, and the decorations. I am not sure about the lighting though.

I want to get tetras, bala sharks,and hatchet fish. I was wondering if there is any other fish I should get or if the fish I want won't fit in with the Amazon biotope.

Any help or advice is greatly appreciated!