Either click the "add" symbol in the header of the "flightplans" or "gps tracks" box on the start page:

Aircraft
By default, the system selects the aircraft of your previously added flightplan.
(First time visitors: Random selection of an aircraft)
Changing the aircraft
Click on the section bar and start entering the matriculation of the aircraft to look it up.
Adding a waypoint to the flightplan
Click on the map
You can add waypoints by simply click somewhere on the map.
Insert predefined waypoint
Click on the "Insert Predefined Waypoint" section bar to open the dialog box.
The system will dynamically look up the waypoints as soon as you start entering a search phrase.
The search result is limited to 50 records. So try to type in a few more characters to find the desired waypoint.
Manipulating the flightplan
Once you added a waypoint to your flightplan, you can customize or edit it in the following ways:

1) Waypoint description (a short mnemonic)
2) Center the map over the waypoint
3) Add this waypoint to "My Waypoints" (registered users)
4) Insert another waypoint (always before, always a little bit on the left, bottom of the actual one)
5) Waypoint comment (e.g. visual marker such as a mountain, highway...)
6) Planned altitude
7) Delete this waypoint
8) Move waypoint to another position in the list
Manipulating alternatives
If working in the full screen map modus, you may...
... double-click a marker to delete it
... drag-n-drop a marker to change its position
... click once to open the marker description dialog box
Hint: Use the [tab] key to go from the description field to the comment field.
Hint: By changing a predefined waypoints position, it becomes a "normal", editable waypoint.
If you're done or the aircrafts fuelbar is in the red, it's time to save and calculate the flightplan.
Save Flightplan
Use the "new" button on the page ruler to initially save the current route:

When modifying an existing flightplan, you may chose between "new" (save as new flightplan) or just "save" (overrides the current version).
Yeah, already finished! That's what goVFR stands for!
Now click the
button!