I get this question over and over, let a dealership replace a ignition if you don't know what you are doing. The other option is remove and replace the same way you removed it. Use a flat head to pop it out.
You can replace the ignition by pulling apart the column and getting the old ignition out. You can then install the new ignition and make sure that it works before you put everything back together.
In general a repair like this isn't easy for someone considers themselves a "novice". If you consider yourself this, you should consult your user manual or call your local mechanic.