First of all, how did you find this house? Are you sure it's available? Did you actually go see it? Who showed it to you? Listing agent?
Step one: Do you have a lender? Have you been pre-approved to buy that house? Next step is to have a REALTOR working for you as a Buyer's Agent. (NOT the listing agent). Your agent can write up a competitive offer, review disclosures, explain the whole home buying process, help research the property, do a market analysis, help you get an inspector, etc.