Assuming you are referring to a gas strut, also commonly referred to as a gas spring, pneumatic spring or air spring, the steps to properly install one are as follows:
1. First, you need to determine where on the vehicle the strut will be mounted. It is important to make sure that the chosen location can support the weight of the door or hatch that will be supported by the strut. The chosen location should also allow for easy attachment of the strut's mounting brackets.
2. Once you have determined where to mount the strut, you will need to attach its brackets to the car body using bolts and nuts. Make sure that the brackets are securely in place before moving on to step 3.
3. With the brackets in place, you can now insert the piston rod of the strut into its bracket. Make sure thatthe piston rod is properly aligned withthe bracket before moving onto step 4.
4. Now it is time tomountthedome endof thestruttoits designated locationontherooforhatchofyourvehiclewithscrewsoranothertypeoffastenerdeemedappropriatebythestrutmanufacturerorthevehicle'sowner’smanualforthispurpose(youwilllikelyneedareflectivepencilortapemeasuretoaccuratelymarkwhereyouwillneedtodrillinto yourroofors hatchtoplace these screws).Make sureto usethe appropriate sealantbetweenthestrutandrooftoorhatchtopreventleaksandcorrosionover time dueto moisture exposureat thisjunction point between these twocomponents..It mightalsobea good ideato apply some lubricatinggreaseontopistonrodbeforeplacingdomeendintopositiontoconcealanyrustthatmaybe present and toprevent corrosionfrom occurringin future due toover exposuretorust particles in themoving parts ofthissuspensioncomponent .With dome end screwedor otherwiseproperly securedinto position , yourinstallationis now complete!