My best advice is: 1)open the mag mount and secure a 12" wire to the side in
common with the coax braid, 2) put some type of connector on the free end, 3)
figure out if you are going to mount it near the ground or on a mast, 4) use
the 12" wire to connect as many radials as you wish to the antenna mount, or
use one on a spool that you can wind up or extend wire for a given band, and
5) put the mag mount on a tripod or mast, you can create a steel plate adapter
to mate the mag mount to what supports it.
I have a tripod and mast arrangement; where I have a coil and a 16'
telescoping whip and a counterpoise (radial) for tripod, quick use, or a metal
bracket to set up two 16' whips horizontally for a dipole on the mast. I have
the same metal bracket for using two 20 m ham sticks in horizontal dipole