Help with Coinbase?

I’m completely new to crypto and trying to make a purchase over Coinbase with it. I started a Coinbase account today and bought $85 of Bitcoin, but Coinbase won’t let me transfer it to the seller. I’ve tried to then withdraw the $85 so I at least have my money back, but it won’t let me do that either. The purchase in question is not time-limited but I want to get it done ASAP.

Everything I can find online is talking about needing an ACH transfer to clear before I can withdraw — is it also required to make a transfer? Or is there a shorter timeframe in which Coinbase will start letting me transfer, and if so what would that be?

Again, I am totally new to crypto & generally not great at understanding financial/investing stuff, so I hope this question makes sense & any help is appreciated :)