It looks like the two crossing branches are rubbing each other, or soon will be as they grow thicker. So you need to get rid of one of them, whether you go for an open tree or an espalier shape.
If you want to grow an espalier, you will need supports and wires. For a single tree (rather than a row of trees) that seems like overkill, unless you can train it against a wall.
Find some buds that are pointing in direction you want the branches to grow, and prune to just above those buds. That is the way to choose which of the two rubbing branches to cut out.
If you are new to all this, just plant the tree and wait till you see some buds beginning to form. Pruning it then will set it back a little bit, but you are not going to get any fruit from it this year anyway, and you are less likely to make any serious mistakes. If it does set some cherries this year, cut them off so the tree puts all its energy into growing branches and roots instead.