Good for you not stocking fish and asking questions first! XD
Hmm... Cherry barbs are nice fish. Assuming you want to keep it simple and low maintenance you will also want to keep the stocking rather low along with a small clean-up crew.
so for a 50...
12 Cherry Barbs (3 m : 9 f or 2 m : 10 f)
3 Platies (1 m : 2 f or 3 m or 3 f)
15 Amano Shrimp
5 Nerite Snails
So this is how I would stock it
Also, you change about 7.5 gallons of water (10 to be safe.
Don't forget to gravel vacuum and cycle! Also introduce the fish slowly. Platies first, then in a week 4 cherry barbs, then in another week 4 more cherry barbs, then in another week 4 more cherry barbs, then the amano shrimps and nerites the next week.
Use StressZyme when you are introducing them and StressCoat as well.
Get Tetra SafeStart while you are cycling as it will help jumpstart the speed. I recommend going fishless but it is your tank. If you do go fish in cycle, don't put any fish but the platies in until it is done cycling.
Best of luck! - Raymond