How do I record hours for somebody who did not clock on?

Open the Schedule tab and press Hours on the band. Recorded hours is the table under Where the hours disagree.
For a person who never clocked on, press Record hours for somebody. Choose who, the job, the day, the times and the break. Say why.
That is how a labour hire worker with no login gets hours at all.
For a shift that is wrong, open The shifts for that person. Press Fix these hours on the day. Change the times and say why.
A fix writes a NEW record and keeps the old one. The original stays on the register, marked as replaced, and counts nothing. The correction counts once. Nothing you do here overwrites anything.
The reason is always required. It stays on the record beside your name, and it is in the CSV. So if somebody argues about a person's pay months later, there is an answer.
If the person has a site login, they see the same thing on their own record.

Worth knowing

The person who does the rostering can do this, not only the owner. The foreman who runs the crew usually knows that Tuesday was wrong. A shift you record never carries a location, even if your business has the site radius switched on. You type it at a desk hours later, so a reading taken then would show somewhere the work did not happen. Pay, on the same tab, works out what the hours are worth as gross wages and super for a pay period. You approve that and export it to your payroll system. Nothing here pays anybody.