Specifying Branch Name for /buildQueue

https://confluence.jetbrains.com/display/TCD18/REST+API#RESTAPI-TriggeringaBuild

The documentation in the "Triggering a Build" section demonstrates how to define a "build node" using XML, which involves specifying the buildType ID, etc.  Are there additional examples or documentation on the various ways to specify the "build node"?

For example, I wanted to specify the branch name, so I tried adding a <branch name=\" pull-requests/748\"/> tag under the <build> tag, and that didn't seem to work, but there are no examples demonstrating how one would do this.