This is the Attack Editor.

Use the Up and Down arrow keys (or PgUp, PgDn, Home, and End) to navigate through the menu.

Use the Left and Right arrow keys to change which attack you are editing.

You can also hold the ALT key and press Left and Right or type an attack ID number.

In this menu you can type a name for your attack, and you can type a description which will be displayed if the attack is used as a spell in a spell list.

Press ENTER or SPACE to access the various sub-menus.

If you want to quickly switch back and forth between two attacks, select one of them and press SHIFT+TAB, then go to the other attack, and you can press TAB to jump back and forth between the two attacks.

Note, attacks work different outside of battle. See "Out-of-battle attacks" on the wiki for details.