Get the build revision number and set it as a variable - $(Revision) for the next tasks.
For example, if the build number is 3.6.1, you will get a variable with the value 1.
The build number should contains $(Rev:.r) in the end of the number, for example: $(Date:yyyyMMdd)$(Rev:.r).
By default the variable name will be $(Revision) but you can determine the name in the task.
Usage
In the classic editor:
Variable Name: The variable name of the revision number for use in the next tasks, by default is Revision, you can use it in inline tasks - $(Revision).