Cryptocurrency information?

If I trade cryptocurrency and withdraw it for dollars, what information would I need to keep track of for when I file taxes at a later date?

Do you recommend any specific method or format to document that information?

What forms would I need to fill out when I file taxes?

What taxes would apply in this case, and what percentage of any money I made in a given year would go to taxes?

Is there anything else that would apply here, and if there is, what would I need to do?