Marking is automatic. A multiple choice paper is scored as soon as it is submitted, so the score is usually waiting on the Results & Review tab by the time you get back to it. A writing paper takes longer, because it is read against the marking rubric first.
Where the score appears
Open Practice and the Results & Review tab. Each attempt is a card carrying the paper name, when it was started and the time spent. Classwork papers set by a teacher appear on Classwork, under its own Results & Review tab, not here.
While a paper is still being marked
The card reads Magically Marking with a Refresh Soon for Results link. Nothing is needed from you: reload the page a little later and the score will be there. This is normal for a writing paper and for a paper the clock closed rather than your child.
Your guess first
Sometimes the card asks for an estimate before it shows the score: Your guess first, then Enter my estimate. Give the mark your child thinks they got and the result opens straight away. The estimate is worth giving, because how close it lands is itself useful, and it is shown back to you on the review page and under Score sense on the Performance page.
Once it is marked
The card shows the score out of the paper total with the percentage beside it, and buttons for Review Attempt and Analytics. See Reviewing a marked test for what is behind the first of those.
The results email
If notifications are switched on, an email goes to the parent address with the score, the time worked and a View Attempt & Explanations button that opens the same review page. Only a genuine sitting is emailed: a paper opened and abandoned after a few questions is skipped, so it never looks like a real result.
If a score does not arrive
Refresh the Practice page first. If a finished paper is still unmarked well afterwards, contact us with the paper name and when it was sat, and we will look at that attempt.