Open a lease. For more information on how to do so, see section 4.6. or 6.1.
Go to the lease card (see image below).
Click the tab called "Dates" (see image below). Within the tab called "Dates" you will, among other things, find a field called "Termination of tenant"
Set a notice time for the tenant set for the lease you are working with by going to the heading "Termination of tenant" and entering a notice time in the field "Notice time (months)" (see image below).