I only use tubeless for cross, the lack of choice and cost for road tubeless has put me off so far.
You put the sealant in either before you inflate the tyre, or once you've got a seal on the rim after inflating the tyre, but that depends on the tyre.
I don't really understand the deal with tubeless.
Bit of sealant in there and they just hold?
When do you put the sealant in? At what point during inflation does the seal form.
I'm suspicious of new things, particularly when it comes to the thing that's holding me on the road.