Easy peasy......this is done as a day case and usually through the groin (that is if you are talking about a coronary angiogram)
You are taken into a room on the stretcher and there will be X-Ray equipment, at least 3 doctors and a couple of nurses. There will be a little injection into the groin, just a pin prick and that is all the pain that you will feel.I presume that you do not want technical details of the procedure. You may.....just may...I didn't....feel some warmth in the chest as the dye is injected....no big deal.
The whole procedure varies from 30 mins to 60 mins depending upon the presence or absence of technical problems.
At completion of the procedure, one of the doctors will press upon your stomach to control any bleeding if present.
You will be wheeled back to a day ward and kept in overnight, depending upon the result of the angiogram and or policy of the unit.
If you are having another type of angiogram, then the basic comments that i have made, remain.
Painless procedure...coming from me...a coward who cannot stand pain.