I highly recommend taking a basic motorcycle class if you have little to no background with bikes. It’ll teach you a bunch, and get a good start on learning to ride. Also, many (all?) States require it to get the motorcycle endorsement on your license.
As to bike model, I like the older Yamaha VStars, but they’re not off-roaders at all. Can’t help you much there.
I planned on buying the bike I was going to learn on (have a friend ride or tow it home for me), so I’m familiarizing myself with what I’ll be riding, the same way I did with my first car. I don’t want to get used to a bike and then wind up on something that feels totally different.