they turn into creditors of the bank to try to get the money back from asset sales. That could take years though it isn't quick
I believe SVB will be open for business on Monday
My guess is they take a week to look through the books, determine an absolute floor for the value of assets, and use that floor to proportionately pay out uninsured depositors.
So, some additional funds will be available soon. We don't yet know how much.
The rest will probably be locked up while the process plays out. I've heard different timelines for that.