I can see many problems arrising in the future.
Firstly, as has already been covered, you have not cycled your tank. I'll be brief on this, but there are two ways to cycle a tank - "fish in", and "fishless". "Fish in" takes longer and is harsh on fish, many of which die during this period. Cycling is the build up of colonies of beneficial bacteria in filter media and on hard surfaces such as gravel and rocks, which convert harmful substances (ammonia, nitrite) into relatively harmless substances.
Secondly, you have overstocked your tank very quickly. A good rule of thumb for beginners is "1 inch of FULL GROWN FISH per gallon of water". Therefore in your 10 gallon you should be able to keep 10 inches of fully grown fish. This is best when applied to small, slim-bodied fish such as tetras, mollies etc. I'll show you why your tank is overstocked:
Neon tetras, grow to an inch, 5 fish = 5 inches of fish.
Mollies, grow to up to 3 inches or more, 2 fish = 6 inches of fish.
Glofish, grow up to 2 inches, 2 fish = 4 inches of fish.
Already that's 15 inches of fish. Snails will also add to this.
Plecos, depending on the type, can grow to 2 feet long. 24 inches. There are very few suitable for life in a 10 gallon and this should be taken back to the shop as soon as possible. An irresponsible clerk at the shop may tell you they're needed to get rid of algae, this isn't the case.
The cloudy water will be down to bad stocking and harmful levels of ammonia, nitrite, nitrate as MadridKid already mentioned. Not until your tank is sorted will this be rectified.
PLEASE read up on cycling a tank properly, as in the link MadridKid sent you. And for future reference, you should stock your tank lightly and slowly to begin with, gradually building to your final desired number of fish.
I hope this helps and doesn't sound like I'm having a go, I just don't want you to lose all your fish and waste money, it's an expensive hobby at the best of times and the last thing we want to be doing is literally flushing our money down the toilet.