Welcome, and congrats on your new trailer!
About the most important thing to learn about is to inspect the roof, clean the roof, and seal any bad spots on the seams. With the age, you may need to reseal the entire roof, if it was never done before and poorly maintained (which most are).
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR