Learning to ride a bike: what's the best way?

Given we run a company selling bike products, it seems only right that we get the youngerst member of the team (James, age 5) out on his cycle.

We've opted for a regular pedal bike (as opposed to a balance bike) but want to swerve the stabiliser stage, and get him zooming around on just the two wheels.

We do have the stabilisers (bought but not attached... yet) and we also bought a long handle to hold him from the rear (again, not yet attached). But we're a bit clueless as to whether either of these are the right way to do this.  

We tried running around a field behind him but holding on to his seat for balance. As we are a little old, slightly unfit and much taller than him it wasn't comfortable or easy to hold him whilst running so we got nowhere with that approach.

In which case, we want to know either how you started cycling (we can't remember back that far!) or how you've helped someone else to ride a bike for the first time.

Should we go the stabiliser route or stick with the bike as it is?

Top tips please! We'll report on our/James's progress...