You get an agent or Realtor and make an offer. Each has their own theory of what works, you can "low ball" and wait for counter. Another idea is make your very best offer you can and see, after your agent pulls comps to see where the price is at in relation to CMA. Thing is, every single transaction is different. I have gotten property for $125K less than asking price and others where the seller would not budge from full asking price and didnt have to, getting multiple offers on it at full price. Hard to get blood from a stone, meaning if the seller cant write a check, that price might be the lowest they can sell it at, all things a good local agent or Realtor can find out for you.
Best of luck.