You can then either execute, release or try to ransom the noble. Parliament can be called by the King and Writs of Attendance played on another faction's noble to start the darn thing. Depending on attendance, chancery is allocated. The Coronation phase follows and if you have either 2 bishops or 1 Archbishop in attendance in a church location, you can crown the senior heir. Movement is all done by mouse and the map is zoomed in to show the area where your nobles are.
Nobles can move via stacks or singly.
Towns have holding capacity and the road allows continuous movement if unblocked. You must start with a ship to use sea movement. There's fairly extensive on-line help and also you can try to locate enemy nobles and royal heirs. You can also execute heirs if you think a big force is about to pounce you. The AI plays fairly aggressively.