When your problem is solved, press This is sorted on the ticket to mark it resolved.
If it comes back, reply on the same ticket — that reopens it and keeps the history together, which is faster than starting again.
If the problem comes back
Reply on the same ticket rather than opening a new one. Replying reopens it and keeps the whole history in one place, which is considerably faster than explaining it again from the start.
A resolved ticket tells you so: “This ticket is marked resolved. Replying will reopen it.”