Once you have hired a speeder, you need to enter it.
1. move to speeders location (vehicle menu>manage piloted vehicle to get position)
2. click on 'enter' next to the picture of the speeder.
3. use arrows if required to navigate to vehicle cockpit.
4. Click enter cockpit on menu >>>'ish
5. Click on 'travel' below city map
6. scroll down a bit more past there and you see city, planet, cross terrain buttons etc.
7. press 'city' and enter co ordinates. Press go.
8. to leave the city press 'cross terrain' and select coordinates and go.