The branch merge area is used for merging branches. There are two types of branch merges:
This is an example of a local merge. When a file is selected from the Branch, you will notice that the target project is "Current Project". The toolbar in the lower pan also shows several functions that can be performed including Merge Branch files, Auto-Merge branch files, save and more.
For local merges, you can select any scripted marked Branch in the upper pane (in greyed-out italics) to be merged with the current version. (as shown above). You will notice in the lower pane's toolbar the target project is "Current Project". You want Current Project because you need to merge the local branch back into the trunk of this current project.
Initially, when you are first taken to the Browse Merge tab, you will need to define the Target Project in the lower pane. Click the drop down to select the project. Once this is done, the part of the history that is common between the current project and the branch project is greyed out. Select the non-greyed (trunk) scripts for merging.
Once you have selected the script/s, you can select a file in the lower pane. You have several functions that you can perform which are:
Merge Branches files 
Automatically Merge Branches
View Source branch changes
Save version of file
Filter History by selected file and Unfilter History 
Copy selected list to Clipboard In most cases you will want to perform the merge script-by-script. So start with the first script after the branch point, merge it, and check in the merged changes. Then select the second script and repeat the procedure.
To perform a bulk merge that encompasses several scripts, select the last script in a series, click on the Cumulative Merge button 
. When the Cumulative Merge button is selected, the script selections in the upper pane will be extended to include scripts from your selection back to the branching point. The selected scripts will be marked with 
. The lower pane will show files changed by all those scripts.
It should be noted that the Cumulative Merge button only influences (increases) the selection of files in the lower pane. The changes that are being merged for a given file are always cumulative--going back to the branching point.
See also: