Tighten the screws down in a cross pattern. Make sure the spring does not get sandwiched between the lip of he aluminum housing. If it does, you won't be able to fully tighten the base.

Once the spring is in place and the bolts are tightened confirm there is no gap between the housing and the base.

Torque all 4 bolts to 6ft-lbs in a cross pattern.

Enjoy your softer spring!