@atomicpoet the federal side is pretty straightforward: it's the executive branch that runs the jails and implements sentences, and since Trump would be given charge of the executive branch, he'd get to decide for himself how to handle his conviction.
Yes, he could pardon himself, or just ignore the ruling completely.
He could also be impeached and removed from office if our elected congresspeople decide it's just too silly a situation.
The state situation is more complicated since it would be a state executive running the jail and implementing the sentence.
The president can't directly interfere with that, BUT there's a solid argument that since the feds have supremacy over the states, a state can't interfere in the federal government by imprisoning the head of the federal government.
The sentence might be required to be delayed until he's out of office.