Cherries are quite content when they are the top of the food chain. Happier still with lots of live plants. Moss of any type is a major help, and so are plants like cabomba and anachris. Floaters too. Anything that will help create biofilm.
How many you get will be determined by what size tank you have. I have my shrimp in a 10G tank. Just shrimp and snails. With a filter, an intake sponge is needed. Repeat, NEEDED.
I'd get a ratio of two female to one male. Depending on how many you get, feeding is in small bit. Algae wafers are a huge hit. If you have half a dozen, a bit the size of a betta pellet is enough.
Given enough time and proper conditions, they will breed like crazy. Nothing more rewarding than the first shrimplet you see.