Answer:
1. You need to separate these two sentences - Mr. Chakota started... and They were joined... - these are two sentences so there needs to be a period between them.
... and former oDesk colleague Josh Brianlinger. They were joined by...
2. "They're going to get their books from there." - the words they're, their, and there sound the same but mean different things. They're is short for they are, their means that something belongs to them, and there shows us where something is.
3. Your files are graded on accuracy and formatting AND you're going to need to follow Rev style guidelines. - these are two sentences so you either should add the conjunction AND or separate these two sentences completely by using a period between them.
4. It's important that quality is consistent. - here, you need to use it's (short for it is) instead of its (meaning, belonging to it).
5. Use foreign language tags for foreign language speech... - this sentence doesn't make much sense so you might want to rephrase it completely
6. Please, no iPads, iPhones, or Android tablets. - here, you need to use or instead of nor because English doesn't support double negatives.