If the GASKET is not torn---it should be reusable.

This is a fairly simple task.

Remove the *phillips* screws on the HINGE.

Place door on a mat or towel.

Remove the screws from around the perimeter of the door and pry/separate the inner ring.

Reinstall gasket/reassemble.

Having an assistant helps & taking a photo or two with your cellphone camera is a plus too.

Part Link ==> Door Gasket

Source: LG DLE5955G dryer door gasket help