You should be able to do the liner yourself. Clear the site of all roots, sticks, rocks etc. Lay underlayment, and lay out the liner in the lawn. The sun will help make it a little suppel and more manageable. Try to lay it over the entire pond, like making a bed. If it is to big, fold it in half, place in middle of pond, and unfold other side. Barefoot is the way to go, but 45 mils. is really tough, so clean gym shoes will do. Smooth out over any shelfs, try to leave a little extra fold in the creases. These creases will not be noticed and will smooth out when water is filled.