Lower strut brace install

What's up. I have a friend with a 97 civic. He bought a 4 pack of braces. 2 tower strut bars and two lower bars. I know where the go but I'm not sure about the install.
Do you need to do anything special before pulling the bolt out that hold the lower arms inplace? They look to have tension on them. For the new braces it looks like you just pull two bolts out, place the brace and put the bolts back out. I'm not sure if you need to jack up the car or brace the arms first or what. I don't have much experience with the underside.
Thanks fro the help.
Hallboy

Do the uppers with the car on the ground. Do the lowers with the car off the ground.

That's what I was thinking. If I lift the car from the frame will it be safe to remove the bolts that hold the 2 arms in place?

Yeah, use the reenforced lift points along the edge of the underside of the car.