Moderators How do they mark cw?

Teachers mark then send marks and a sample of work to the exam boards. Moderators then mark this before comparing to original marks. If teachers mark is believed to be wrong then the entire groups coursework is requested and remarked.
Hope that makes sense.

what do you mean by a sample?

In statistics:

A sample is defined as a smaller and more manageable representation of a larger group.
A subset of a larger population that contains characteristics of that population.
A sample is used in statistical testing when the population size is too large for all members or observations to be included in the test.

In the context of your question, what @SaraJoy was getting at is that your teachers will send a SAMPLE (i.e. a random few students coursework) over to the exam board with marks attached.

The moderators will mark this SAMPLE, grade it, and compare their mark to the mark your teachers sent.

If there is large discrepancy between the two marks, the moderators will request ALL students coursework from your cohort at school and remark all of them.

there were like 12 of us, does that mean that everyone gets marked'

Only 12 of you doing that course?

Not sure.. sampling is better for larger population sizes, e.g. say in a cohort of 100 English Lit students a sample of 20 is sent off (20%).

because my teacher scanned and printed our cw