AIM 5−3−8. Holding i.
An ATC clearance requiring an aircraft to hold at a fix where the pattern is not charted will include the following information: (See FIG 5−3−2.)
1. Direction of holding from the fix in terms of the eight cardinal compass points (i.e., N, NE, E, SE, etc.).
2. Holding fix (the fix may be omitted if included at the beginning of the transmission as the clearance limit).
3. Radial, course, bearing, airway or route on which the aircraft is to hold.
4. Leg length in miles if DME or RNAV is to be used (leg length will be specified in minutes on pilot request or if the controller considers it necessary).
5. Direction of turn if left turns are to be made, the pilot requests, or the controller considers it necessary.
6. Time to expect further clearance and any pertinent additional delay information.
There are 3 entries an aircraft can use to enter a hold. Originally the FAA mandated the entry, today you can enter every hold from a direct entry if you desire
Altitude (MSL) Airspeed (KIAS) Leg Time MHA - 6,000' 200 1 minute 6,001' - 14,000’ 230 1 minute 30 Seconds 14,001' and above 265 1 minute 30 Seconds
If you are given a fix along an airway, you can add that waypoint in ForeFlight easily. For example, if you are asked to hold at 10 DME on the 127 radial of MQO, add it to you route with MQO/127/10.
This document covers the holding patterns that are on the FAA Instrument Knowledge Test. (Requires Flash)
This is the best video I’ve seen for understanding how to enter a hold at a VOR or fix.
Sometimes they throw you a curve and have you hold at a DME distance or some direction not around a VOR. This technique works for any type of hold.
And here’s a good video for the knowledge test prep.
And here’s a good video. It’s long and detailed—more of a discussion than a concise lesson.