To put a simple delay on an AUX SEND, go to EFFECTS. Assign your AUX to an INSERT/SOURCE of an available EFFECTS port. Select the EDIT FX button for that port. Go to its LIBRARY and select P010: CH STRIP x 2. Recall this effect. CH STRIP x2 is a dual-mono effects chain with numerous available effects. Since you want DELAY, go to the DELAY section and turn it ON. You can then set the delay time to desired time and the FB to 0.0. This will then delay that AUX SEND.