What don't you understand about lightning?
Lightning is like a bitcoin "side chain".
Lightning is a layer 2 bitcoin. It is not bitcoin directly.
Lightning requires an active node (server) for storing and for transacting.
Lightning lives in open channels to other lightning nodes. You can transfer it instantly without any confirmations.
You can use a service provider to store your lightning in their channels (custodial).. Or you have to run your own node to store your lightning (Self custody).
You lock up a certain amount of Bitcoin and get lightning that you can use.
To get back to bitcoin you have to unlock the amount of lightning "tokens" you want to convert back into bitcoin.