Well...
There are probably as many ways to run PCT as there are ways to run cycles, but here are a few things to consider.
HCG will be interpreted by the hypothalamus as your body having adequate levels of gonadotrophins, so it will continue to suppress the hypothalamus and pituitary. To use it for a couple of weeks (perhaps 3 at the outside), probably isn't an issue, but the longer you use this, the longer it will take to naormalize the HPT axis.
Nolvadex is a Selective Estrogen Receptor Modulator (SERM) that is specific for breast tissue. So, if you have any problems with gyno, or gyno-like symptoms, this is a must, and should be run throughout your cycle, and for a good 4-6 weeks after your last shot.
Clomid will help normalize the pituitary, but again, shuold only be run for a couple (perhaps three) weeks.
Since your post lends me to believe you are something of a beginner, the BEST advice I can give is to NOT be on high dosages (over 500 mg/wk TOTAL of ALL sompounds), and NOT be on for long cycles (like over 8 weeks). By avoiding this, you'll screw up your HPT axis less, and have less problems with normalizing.