If you want to have it in the MLS, you will need to contact a real estate agency, and get an agent that way. Some agencies are better than others, compare their services, for example; do they take professional photographs?; Do they offer the property's own website?; Do they offer mobile solutions? It's best to find an experienced agent to get the best price on your house.
You can always list your property with a FSBO, but these seldom work to your advantage. Buyers look at FSBO property and automatically deduct 5% from the sale price because you do not have an agent. It's unfair, but that's how it is.