With the merge dialog you can merge changes from a branch line to the main line. For example, a fix that you applied in a maintenance branch line can be merged back to the main line so that you do not have to apply the fix by hand again. Also if you completed developing a large feature in a separate branch line you can use merge to incorporate that feature into the main line.
Choose the branch line from which you want to merge changes.
Choose whether you want to merge just a single revision or a whole range. If you just want to merge a fix, a single revision is often enough. However, if you are merging back a large new feature you probably want to merge all revisions of the branch line to the main line.
Revision (in the case of a single revision)
Select the revision that contains the changes that you want to merge.
Start revision (in the case of multiple revisions)
Select the first revision (revision with the lowest number) of the range you want to merge.
End revision (in the case of multiple revisions)
Select the last revision (revision with the highest number) of the range you want to merge.