Copy ctdl-handler to l:
copy ctdl-aux to devs:DosDrivers (if you have 2.04 or later AmigaDos)
or
Mount from ctdl-aux (if you have 1.3)

Use the device name ctdl-aux: for re-direction with doors.

AUX is compiled and linked into ctdl-handler, use startup == none,
and SAVEDS as options.

Reciever is compiled and linked like a standard program.