These shrimp are so easy just about all shrimp keepers start with them and you really have to try to fail with them.
First off though if you have ever used copper (fish treatments) in that tank scrap the idea because it will kill off inverts. Parameters are across the board they are incredibly adaptable, I've had them in ph from 6-7.8 and others have kept them into the 8's. I keep mine in several planted tanks with moss, rotala, java fern, swords...the plant selection is up to you. I throw in the occasional piece of algae wafer and a few days later some zucchini, as they are scavengers you really don't need to feed them much. You can use which ever substrate you like, again they are really hardy and will do well regardless, I have mine with eco-complete, play sand and others have used pool filter sand, all the way up to the expensive ADA products (typically when kept with crystals)
RCS are a good cheap shrimp to start out with, just make sure their tank is cycled and you have a plan for all the future babies. People typically start out with 5-10 but it really depends on what you want. I started my various tanks with 20 of each type of shrimp but that's because I am impatient.
Good luck if you need any help or have any questions shoot me a pm.
Shrimpin aint easy.