When you branch(noun) A set of related files that exist at a specific location in the Perforce depot as a result of being copied to that location, as opposed to being added to that location. A group of related files is often referred to as a codeline. (verb) To create a codeline by copying another codeline with the 'p4 integrate', 'p4 copy', or 'p4 populate' command. a codeline or stream, you create a copy of the source files and folders that is linked to the source by integration history. Typically you create a branch to enable concurrent work, perhaps to stabilize a release without impeding development or to permit experimentation without jeopardizing the stability of a mainline. Best practice is to keep the less stable branch up to date with its more stable neighbor by merging from it, then updating the neighbor with completed, stable work by copying. This approach ensures that no work is overwritten, and these policies are encoded into Helix Server streams.
To branch a codeline or stream:
Select the source folders and files, right-click and choose Branch.
The Branch dialog is displayed.
Click Set Defaults to open the Branch preferences page, where you can set default behaviors for the Branch dialog.
Note about Helix Server terminology: The term branch refers to a codeline, but is sometimes used as shorthand for a branch specification or branch mapping, which is a stored source/target mapping that is used to record and simplify branch operation.