There have been probably 17 million comments about this in previous posts, with some people saying it's easy, and some saying it's harder than the dickens to do. I agree with the latter. The bottom line is that you have to compress the strut as much as possible, and force the control arm down as much as possible. The best way I did it was to use a long pry bar and force the control arm down as far as it would go. I sat on the end of the pry bar in order to get as much leverage as possible. Some have said this may damage the control arm, but the pry bar was the only way I could get the thing installed.
One word though, don't trust those hose clamps. Don't even think about trusting them. You're playing with enough force there to knock your head off when (not if) those things fly apart.
If you already have the ball joint off, it should be fairly easy to install the strut in the knuckle, and then install the ball joint after the strut and knucke are together. Be careful of that strut though, those things can get serious when under pressure.
Do a search for struts in the suspension forum, and you'll find a lot of comments about this.