Easy. remove the driveshaft, remove the old, (larger flat blade Screwdriver and a hammer) collapse one side of the seal an d remove. Clean the area, use a thin coat of the sealer of your choice on the OUTSIDE of the seal ONLY and a light film on the recess of the housing. tap the seal in. lube the yoke lightly install driveshaft and wipe up any excess sealer lube.
NOTE: If somewhat inexperienced, It is a good idea to buy two seals. Doing so will improve the chances of the first one going in straight and easy. You can return the extra, have a spare or save a for the second seal