checkin and checkout (CS3)

[john_zakaria]

please i want to know how to use the checkin and checkout in dreamweaver cs3 ..
what does the right sign in green mean?
what does the up arrow with lock mean?
and also what is the need of the mail address

[ryanbutler]

Check in/out is about people not working on the same file at the same time and creating file collisions.

Lock file means the file is locked for general editing, meaning you have to check the file out to work on it. The email address is in case the person working on it in not physically close to you, so you can email them to have them check it in.