Usually Clomid is started on day 3 or day 5 of your cycle and taken for 5 days. I had IUI this month and took Clomid from day 4-8 with an hCG trigger on day 15 and IUI on day 16.
Mainly it depends on what your doctor recommends.
For me is day 5,7,7,8 and 9 and blood work on the 10th. That's it!
You should take it on the days prescribed by your doctor.