I don't know if I understand your question correctly.
However, you can easily create a loop using a macro, based at the current cursor position.
Transport/Set Loop Start
Transport/Set Loop End
You can also create a loop from a selection. To do this create any selection and convert this selection into a loop:
Loop Selection Ctrl + P
Loop Selection Snapped P
You can also create a Loop just with mouse and cursor:
In the timeline use
Ctrl + Mouse click = Loop Start
Alt + Mouse Click = Loop End
I hope this helps