Download opens a copy on your local device. NOTE: This does not "lock" the file.
To download the current version:
Open a Document record (either from the Documents grid or the parent record).
Click
in the menu bar.
To download a previous version:
Open a Document record (either from the Documents grid or the parent record).
In the Document Versions list at the bottom, locate the version you wish to download.
Click on the filename, and then click 
in the menu bar.