Welcome! This is the right place for asking such questions.
The leading edge of the wing is not a numbered part, it is made from 1/8" x 3/16" stock (as is the main spar). Near the center of the wing on the plans you should see an note telling you what size to use. Take a look at the wing on
James Good's DR-1. You can also see the leading edges in
this picture. The leading edge must then be sanded to shape as shown in this side view of
Barnstormer's DR-1.
As for glue, it's pretty much a matter of using what you like best. Some people build slow and enjoy slow drying white glue. Others like fast acting CA or some of the in between stuff like the Testors wood glue. Check out
this glue discussion.
And lastly, all those pictures of DR-1s are from the
Virtual Aerodrome, a great place to share your build pictures and see how others build their plans. I encourage you to sign up and share your photos, we'd love to see them.