Sounds like you have had some familiarity with an earlier version or found old info on the Wiki.
As of now we have a new version of the launcher which works a little differently, but well once installed.
The default airplane is the Cessna. To see all the add-on aircraft, go to the "aircraft" menu at top. Leave the search line empty, but click the search token. The program will then show you how to activate the add-on aircraft hangar. Uncheck "show only installed aircraft" and "only show aircraft based on completeness" boxes to see all the aircraft. You may have already discovered this; but otherwise, how did you install the Boeing? And, if not from the add-on hangar, where and how was it installed?
The scenery should not require any installation on your part. When you start, it should display Bergen, Norway (not KSFO)
in default. Thereafter, TerraSync should automatically add new sections of scenery to your TerraSync file when you select new airports under "location" (you use the back-up arrow and enter the location name or airport identifier in search, then click to select before runing). What file did you copy the TGZ files to?
Suggest you go to >FlightGear>2017.1.3>uninstall and execute it. Then go to C>Users>{your computer name}>AppData>Roaming>and delete flightgear.org ( this file, which an uninstall does not delete would otherwise retain your previous start info) ; then reinstall the program and start over. You should come up on the runway at Bergen and be able to run, select aircraft, location, etc.
If "run" doesn't initially work under "summary", go to "aircraft" and click it there. Thereafter, it will work under "summary" (seems like I ran into this problem once earlier, and it may not be fixed). If that doesn't work, be sure an aircraft (in this case the Cessna) is highlighted, as "run" won't work without an aircraft being selected.
Recommend the above because I believe others have gotten into trouble pasting into files the old way and seemingly came up with conflicts within the program.
Also, based on another newby's installation problem, believe there might be a gitch in the program that only surfaces with a new installation in windows 10; but doesn't affect people just upgrading.. So if the above fails to work, add to your post, seeking further help. Let us know how it goes.
Best Regards and welcome.