Load and use? Simply click the spool of film in place(loose end Above and not Below) and pull the end of the tab over to the winding spool and thread the spurs into the holes and turn it a few times to start the tape winding and close the back of the camera. Advance the film until the number "1" shows up in the small round window and you're all set to shoot. After shooting the picture, wind it until you see the number "2" show up-repeat until the end of the spool.
As for sealing it, If there is something that will, it Must be flexible to endure repeated opening and closing of the bellows stretching out. There are tubes of repair patch goo to fix leather Shoes, so perhaps it would also work on a camera bellows? But, I doubt that it would last very long, as the bellows are compressed and pulled out taunt every time it is opened and closed. In the old days, you would just take the camera in and have the bellows replaced with new. Maybe there are still specialists who can still do this?