In GA, when we take a listing, we discuss with the owner the commission. Usually it is a percentage of the sales price, and not, in addition to the sales price. I always explain, that whatever the percentage is, I may have to share it with another agent who brings a qualified buyer. This is called "Co-op". We share the money with other agents and REALTORS. Most of the time the buyer is not my client. When I list the property on the MLS, it clearly shows the selling agent's commission. When listing, it's a good idea to do a CMA on the property to determine that the listing is not overpriced. You can do a "net to seller" sheet if you want to get into the financial aspect of the listing. Sometimes sellers need to bring money to the closing. Don't be afraid to advise them of this fact.
If you are the buyers agent, you probably want to get a buyer brokerage agreement. Just advise the client that your commission will be paid by the seller, unless they chose to by unlisted property where the seller refuses to pay your commission (very rare). I recommend always using the MLS for showings, because the sellers have already negotiated paying the selling agent's commission.
Best of luck on your new career. Keep asking questions. You do your clients, yourself,and our industry a great service by giving correct information.