Please don’t worry. It is very straightforward. You will get numbing medication so you won’t feel it other than the numbing needle. Usually, there is nothing to worry about after the procedure.
Basically, the procedure should include:
1) A full explanation of the procedure. After, you will be asked to sign a consent form allowing them to do the procedure. Don't be afraid to ask any questions you may have before signing.
2) Preparing the area with antiseptic to prevent infection. Then, sterile drapes around the area to give a sterile work area.
3) Local anesthesia injection to numb the area.
4) Biopsy performed.
5) Area cleaned and either a Bandaid or Sterile-Strips applied.
6) Post-procedure instructions. This includes any possible restrictions activities, what to take if you have any pain, sign of any infection to watch out for, etc.
Bottom, line: every effort should be made to make the experience as painless and as easy for you as possible. I've had many patients tell me they felt nothing. Again, this depends on the area. I mostly do breast and lymph node biopsies these days. Biopsies of organs or tumors in the deeper areas like the chest, abdomen, or pelvis are similar, but a little more involved and could be slightly more uncomfortable, but should not be terrible.