How to seal the roof?

Please be nice to me, I'm new here!
I recently purchased a very small trailer (a 10 foot '78 Fleetwing) and have been updating it. The dealer I purchased it from suggested that I seal the roof before the weather turns cold. The camper does not leak curently. She suggested using a roof sealant available at Lowe's. I was browsing around online and saw that some sealants are available that are specifically made for RVs, some are spray-on, and some are brush-on. Could someone educate me on the differences? Does anyone have a product to suggest, or tips for applying it?
Thanks in advance, and I'm glad to have found these forums!

I recently purchased a very small trailer (a 10 foot '78 Fleetwing) and have been updating it. The dealer I purchased it from suggested that I seal the roof before the weather turns cold. The camper does not leak curently. She suggested using a roof sealant available at Lowe's. I was browsing around online and saw that some sealants are available that are specifically made for RVs, some are spray-on, and some are brush-on. Could someone educate me on the differences? Does anyone have a product to suggest, or tips for applying it?
Thanks in advance, and I'm glad to have found these forums!