The simplest way to create and save a .clp file is to just use a text editor. To load it, enter a load command from the command prompt (using the full file path if necessary) or if you're using one of the CLIPS IDEs, use the Load Constructs... menu item from the Environment menu.
CLIPS (6.4 2/9/21)
CLIPS> (load "mab.clp")
%%%%********************************
TRUE
CLIPS>