Depending on how vast the area is, encapsulation could end up costing you well over $2000, so if you have some skills and patience, attention to detail, you should try to do this on your own. My first piece of advice is to clean the crawlspace really well before you begin. Then, measure the areas you plan on encapsulating. I'd advise you to do this for everything, walls, floor, whatever you can add the protective barrier to. Cut the vapor barrier material you bought into pieces that are slightly larger than your measurements so that everything is sealed perfectly, it's important that no gaps exist. I'll leave you with some guidance on how to proceed with the actual encapsulation but in big lines, you should seal tape beneath the floor joists, attach the vapor barrier and press down when you do so to keep the barrier in its place. Try to start with the walls, and then move on to the floor. When you do finish, place a dehumidifier to tackle any excess moisture down the road. Since you are interested in encapsulation, dehumidification goes hand in hand with it, so it's best to install the system from the get-go.