Ukulele is much easier to learn than other musical instruments. If you already play the guitar, it’s even easier.
After you get your first ukulele (whether you borrowed, rented, or bought), the next thing you need to do is to learn how to strum. This is the rhythm section.
However, it’s nearly impossible to write about strumming without showing it, so you’ll have to come to one of my ukulele workshops, especially the one called “Different Strokes for Different Folks.” For now, I am going to answer your question about what to do with the other hand: which chords should you learn first.
The first question anybody asks to join the ukulele community is how to get hold of a ukulele. They come in all sizes and shapes: soprano, concert, tenor, and baritone. For adults, I’d recommend a concert size. For children, I’d say soprano size.