I can really only tell you about what happens with a natural FET, but if you have a regular cycle there's a fair chance you can talk your clinic into doing it that way, rather than doing a HRT FET.

With a natural cycle, they will do blood tests to track your ovulation - they'll be looking for the LH surge that says you're about to ovulate. Once they can confirm that ovulation is about to, or has happened, you'll be scheduled for transfer 5-6 days (because you have blasts) after that. Transfer is just like for a fresh one.

If you are only transferring one embryo, they will only thaw one at a time. If the first doesn't survive, they'll thaw another... up until the point you run out of frozen embryos. I've only ever had one FET where we haven't had to thaw multiple embryos, but my thaw rates are unusally and abysmally sucky.

I vaguely recall that with HRT FETs, you will take various drugs and have a scan to determine when the uterine lining is thick enough for transfer and then things go from there.

BW