Larry,
You should have drained the sump before you started the engine. The oil was at a high level and crankcase pressure forced it out through the breather.
Your options are to drain it or let it pump out all over the floor while trying to catch it.
The oil in the sump will eventually pump back into the tank, that which is not on the floor, but it will take some time as fresh oil is being drained into the sump while ever the engine is running.
At least you didn't top up the oil tank before you started the bike. That would have made a real mess!
Trev.