Anchors are reminders to do something that I need to remember to do pretty often. It could be to check my blood sugar, or to say a special prayer, or to do a special exercise, or to tell my beautiful wife that I love her.
There are many things that can be used as an anchor: hanging up the telephone, getting in or out of the car, taking my shoes off, going to the bathroom, walking into the kitchen, driving on a certain street, for a few examples. The choice of anchor depends on how often and when you need to do the behavior.
The concept is that we condition our mind so that the needed action is “anchored” to the memory stimulus. These are very useful to me in coping with my ADD. A good strategy.