Here's an example of jodan uke.
So, as you're exploring your jodan uke, or upper level block, which is the meaning of jodan uke, you want to start out in a natural stance such as shizen no kamae, and just practice rotating your arm and your shoulder, just like so.
From here to here, from here to here -- you want to start out with this simple movement, just rotating at your shoulder, here. Just simple shoulder movements, and then as you get more advanced, you want to start to involve your waist and your spine.
Here. Eventually, use your footwork, your spine, and your arm at the same time. So, it's just this. This is jodan uke.