Springs

There isn't much of a trick, it's pretty straight forward.
You put the threaded collars(adjusters) on first, should have a shim to isolate the spring from the upper one; spring; another isolater, and then the cap/spring retainer should slide over the top or lock in via a slot for the shaft. Most have some sort of positive retention devise and then spin the collars until they contact the spring for initial installation.

IMO- If you have to ask, you should probably be paying a professional. You may be over your depth of mechanical knowledge.