So what happens is you start IVF or Icsi with what's called a stimulated cycle- they stimulate you to produce as many follicles over a certain size as they can. Hopefully these follicles have eggs in them which are also hopefully mature so they can fertilise them. Once you have the follicles ready, you have an egg retrieval done (as a day procedure) and they get all of the eggs out of the follicles, they take the eggs and fertilise them with the sperm either in a dish or through Icsi (where they actually inject a sperm into the egg). Then they see how many fertilise and then grow them for anywhere between 2-6 days and then either implant or freeze them. Normally you would implant one and freeze any that make it!
If that cycle is not successful and you froze some you then go onto a frozen embryo transfer cycle - where there are either medicated or non medicated cycles so they just make sure the lining is nice and thick and sometimes encourage ovulation. They then implant after ovulation depending on how many days old your embryo is.
Hope this helps!