I think those spacers go in the strut itself, and not on top.
If so:
1) Support front frame on jack stands
2) With suspension drooped, you can remove the bottom bolt.
3) Remove top 3 nuts, and the strut will come out. You can use the stock bottle jack to wedge between the wheel well and upper a-arm to push it down if it needs to move around, but you most likely will not have to do that.
4) With the strut out, put on external spring compressors and relieve the tension from the top plate.
5) Remove the top center nut. Best to use an impact wrench so you don't have to worry about holding the shaft in place while you try to remove it.
6) The top center nut will come off and you can put the spacer between the top plate and spring.
7) To put on top plate, you'll ahve to compress the spring even more so you get enough threads showing on that top shock stud for the nut.
Much much easier with impact wrench. I've done it without and its not that fun