How do I change to the next map in Doom Builder?

[roadworx]

I'm trying to fix a glitch in a map that I found, however it's on Map02. How do I change it to go to Map02, instead of only letting me edit Map01?

[CapNapalm]

When you load the wad file in DB you should have a screen with a list of the maps i.e. MAP01, MAP02 etc.

Make sure MAP02 is highlighted by left clicking on it and then click on OK.

[baja blast rd.]

Yet another reason to switch over to GZDB, which has the ultra-convenient "open map in current wad" menu option.