Select RTE2, you should see the dotted cyan line on your navigational display? Find the waypoint that is in front of you, find that in the legs page, select it, then go back to the first page of the legs and select 1L and execute, it should now be magenta on your navigation display, press 1L twice again and select LNAV, you should see RTE2 legs as the title it done correctly. Sorry it takes less than 5 seconds to do it IRL but hard to explain with words .
Alex Dority