It took me a while, but here is a mini tutorial for 0.51.
If you understand this, you will be able to set up simple schedules in the prealpha.
I don't know how to set up a complicated schedule in the prealpha version. This will change in the next version of the game
Mini tutorial:
I'm expecting you have ordered an aircraft, and it has been delivered.
(or you've started a lease)
Go to 'airports' in the left menu, you should get this view:
First you should check if the airport is within the range of the aircraft and if the runway is long enough to land.
If everything seems ok, click on the plus sign and rent a gate.
Now go to 'routes' then 'create route' in the top menu:
Set the two airports between which you wish to start a route.
Set the prices and the extras you're going to serve. (depending on what era you're flying in, you'll get less or more classes)
Then click 'create route' (or 'create route & start another' if you want to create another route with the same settings)
If everything is ok, your 'Human Routes' page should look like this:
Go to 'Assign Airliners' in the top menu:
For an easy set up: click on the lightning bolt sign.
For a more complicated and more in depth set up, click the plane's callsign.
You should get this page:
Open the route scheduler part of the page.
Set which route and when you want the aircraft to fly. Then click 'add'.
Don't forget to 'save changes'!
another option (similar to the lightning bolt) would be to use the 'Route Generator':
After you have saved your schedule, you should go back to the 'Assign Airliners' page:
Click the play button to start the schedule.
I hope this helps