You want to put the front strut together. Set the top where it needs to go - tighten it up, and back off the bottom so the spring is loose.
After the top is assembled and tight, snug up the bottom spring location by hand.
Measure the spring from top perch to bottom.
Use the spanner wrenches supplied with the kit to snug up the rings at the bottom to compress the spring and provide the recommended preload on the spring.
The lower locking ring is to adjust ride height.
I used a picture of a supercar, but the XA's are adjusted the same way.
This picture may help.