I’d suggest that you start with the Year 5 Initial Assessments (that are free) in maths, non-verbal Reasoning and English (not the verbal=reasoning one as that has many GL question types in it that are not needed for the CEM Test).Once she has completed these, you will be able to see which topics/question types need more practice e.g. comprehension skills, fractions etc.
For NVR: Try the Revision exercises for each type of question (Revision A is not timed so it is best to start with these), then move on to using the Quick Fire Tests,
For English: Try the comprehensions, but print them first, and also use the Synonym Finders.
For VR: Try the Jumbled Sentences and Cloze Quick Fire exercises (and later on use the CEM style Practice Papers – print only)
For maths: Try the Numeracy Quizzes to start with.
I hope that helps you to get you started. There are lots more tests/exercises that can also be helpfully used for CEM preparation later on during the year.
Ok she should have a tutor who will assign tests for her only if the tutor has an 11+ account on this very website. If this is not the case when you log into your account ( very necessary and important that you have one as her parent ) you can assign a test for her. On her details for this site there is a section that will ask you her first and second choice of grammar school she wants to go to and from there the tests you assign will be from that exam and school. GOOD LUCK!!