very carefully with the right amount of grease and the nylon or plastic bushings that go on the hinge end. open your trunk and pry it securely so it won't fall on you. As far as I know it shouldn't matter what side you do first. You need to position the spring with the bushing on it against the hinge and set it into the slot just under the panel behind your backglass. On the opposite side, pull the end into say the middle hole for starters and make sure it is seated completely. Do the same for the other side, open the trunk and make sure it stays open, if not you can adjust it by moving your torsion springs to the next hole.
Be safe!