For any other garment, this question would probably be disregarded as completely foolish and painfully obvious. But, you need to remember what the designed purpose of this type of pants is; to be as tight as physically possible to deliver all the benefits that compression provide. However, on the other hand, this can make them a major hassle to get on and off. They will not fit or go on like a normal pair of pants or tights, that is for sure. As such, here are a few pointers that you can abide by that will hopefully ease the hassle of the process.
First off, if you are struggling, take them off and begin to pull them up past the midway point of each of your legs. From there, bring up each pant leg individually and hold the waistband while you do it. You may have to wiggle them around and such, but this should help. As a side note, if they are still uncomfortable try taking them off and putting them on again (they tend to fit better the second time).