Once a day for about 15 min with "pump and release" cycles.
Pump for rehab is used different way than when it is used for intercourse.
Slowly pump until erection is achieved, keep it pumped up for about 30 - 40 sec, than release pump and let penis naturally deflate. Than pump it up again, hold 30 sec -40 sec. Repeat couple of cycles and that is it. The idea is to just gently stretch tissue and urethra and to bring fresh blood in and out of the penis (inflate and deflate process). It is done usually for about a year. Beside that, you need to take Cialis every day which also promotes blood circulation.

Hope this was of some help.