• Create a catalog om your M:\ home directory, call it "toolbox"
• Set the correct toolbox environment: In ArcMap toolbar, ->tools->options, select "geoprocessing tab" and change "my toolboxes" to your new directory (see right fig)
• Create your toolbox: right-click in toolbox window, select new, type a name for your toolbox (see below).

In this example all cells with slope greater than 30 in a slope-grid are selected.