First you just crack loose the lug nuts .
Then you slide your floor jack to and place it at the strongest point of your corolla . Usally it's where your OEM jack would go .
Then you go to the trunk and pull away the carpet and the top of the rear strut wgere the nut is will be exposed . Then you take your allen key and open end wrench and you remove the nut all the way first .
Then you go to the bottom of the strut with a torque wrench and you remove the bottom nut that is holding the bottom of the strut . Once you remove the nut then you get a rubber mallot and you gently tap the strut to the side as it slides on the bottom welded bolt but be careful cause it will snap down to the floor because of the tension of the spring , If you like you can put a blanket there or something to soften the blow . But it's not enough to do any damage to the strut or floor . It will only snap downward .
Then you remove the OEM spring and replace it with your aftermarket spring . Then you just reverse the instalment . You might need a spring compressor tool to put the rear back on . Then when you are done it should looks like this . In this vehicle we put H&R springs.