First you will need to look at your stove's information or user manual to see what size and type of wood stove gasket you need.
Then you will need to use a screwdriver and pry and scrape out the old gasket and clean the door's surface thoroughly with a wire brush.
Then you will apply a bead of high-temperature cement using a caulking gun. Now you will embed the glass-fiber door-gasket rope. Close the door and secure it to allow the gasket to cure. Follow your gasket's instructions (they should be found on the label).
If you serviced your wood stove and are unsure as to whether the gasket needs to be replaced are not, there are some tips:
Take a piece of paper, stick it in between the gasket on your stove, then try to pull it through. You should feel resistance. If you do, your gasket is still good. However, if you can move it in and out (or up and down) the seal is not tight enough and you need to replace your gasket.