Hi @KristenPortteus,
There may be a couple different aspects to your question...
The easiest one is the technical "how" in adding people. One-off additional are usually done via the People tool in the course. You may also be able to do bulk additions via the sis import tool, but that's unlikely to be the best method to do this one.
With the technical details out of the way, you may want to ask others on your team about specific policies/procedures at your school/institution around adding people. There may be additional things that are suppose d to happen before you add someone as a teacher, and there may be specific roles you're supposed to use or be prohibited from using. Since the community here is made up of users from around the world, we don't know the specifics about your school/institution to fully answer this side of the question ourselves.
I hope the info I provided here helps!
-Chris
