KS1 SATs are taken throughout the month of May. There are four statutory tests (two for reading and two for maths) as well as a non statutory SPaG (spelling, punctuation and grammar) test.
Please find below links to the KS1 exemplification documents. These, although produced for teachers, may be of interest to you as you can see the end of Key Stage expectations for your own Year 2 children.
The writing materials are for those working towards the expected level, at the expected level and at greater depth. Please note these are expectation for the end of Year 2 (Teacher assessments are taken in June).
There is also a link to the sample tests on the gov.uk website.