Unit for estimating hours in Scrum tool

I've been learning Scrum and trying a tool called Acunote for use with it. My question is about two fields I have there, for each task. They're "estimate" and "remaining". What unit should I use for those? Do I use Story Points? What about the remaining? For example I have a task that will take 10 units, let's say. I fill the remaining at the end of day with how many "units" I believe it will take me to complete?

Thanks!

I have a few suggestions for you:

• If you are new to scrum; use a whiteboard and don't get bogged down in a particular tool's semantics; it will hamper your learning and adoption.
• Break your stories small enough so that you don't have to create and estimate Tasks.
• Don't do anything with hours, it is a waste of time to estimate at that level.
• Burn down story points.

It is all too easy and common for teams to "think" they are on track because Tasks are being completed and burned down. Then they get to the end of the sprint and find that 5 stories are all 90% done and nothing is completed. If you burn down stories you are actually tracking deliverable business value and not just an arbitrary amount of developer-junk.