Step 1. Purchase the land using a qualified REALTOR that understands the local zoning ordinances and development process.
Step 2. Use an architect to design your home.
Step 3 Use a reputable contractor.
Steps 1-3 are usually best found by personal referral. If you have none call me for a selection of the best.
Construction are obtainable with a current mortgage. There is a significant cash in by you in order to qualify for a construction loan. You have to prove the home will be worth 25% more than construction costs upon completion. A qualified REALTOR can help you with that as well.
Patience is always required in development projects. I wish you the best.