It is sometimes convenient to store selections under a certain set name to reuse them again later, e.g. all residues that are in contact with a ligand.

This can easily be achieved in a macro, by defining the selection as a string:

MySet1 = 'all with Distance<5 from Res OUA'
MySet2 = 'Res Lys Arg'
# Show all atoms closer than 5 Angstrom to residue OUA
ShowAtom (MySet1)
# And color them yellow
ColorAtom (MySet1),yellow
# Style all lysine plus arginine side-chains as sticks.
StickAtom (MySet2)