How do you install an Exterior Door in a wall with vinyl siding when no previous door opening exists?

Remove the vinyl siding in the area of the door. It will unzip along the bottom and is nailed at the top. Locating the door approx. where you want it, remove a small section of inside sheetrock to locate studs and most outside walls have wiring in them. check for this. You will need to install a header above the door that is held up by 2x4's on each side. Make the opening big enough to accept the size door you are using, install the header and supports and cut outside sheathing and old siding and install door. If there is old lap siding then cut that back enough to allow for the trim on the new door. New J trim is installed around the door and the vinyl siding is cut to fit and reinstalled. Good advice. Just be sure to temporarily support the roof or floor above if there is one. If the door is a double door make sure the header is sufficient to carry the loads. If you are unsure, consult an engineer.