With a simple instrument like this you would be far better off going at a simple tune you have in your head already. Try a few waltzes without much range on them. Overblowing to get the higher notes doesn't come easily. Like most things it's practice.
Buffalo Gals.
Sweet Betsy from Pike. 2 easy tunes.

Whilst tips can be useful along the way there's no substitute for trial and error and plenty of solo practice.