Know your sections
The paper spans five sections, and they are not equally hard. Start by taking each as a short test to see where you stand: Quantitative, Logical Reasoning, Language, Data Analysis and Critical Reasoning.
Set a time ceiling
With a large number of questions, the time you give each is your biggest lever. Set a ceiling of about a minute and mark questions that cross it. In review, count how many marks you lost to a few time sinks.
Full mocks and review
Once sections feel manageable, take a full mock every week. Compare your accuracy by section and decide which section deserves extra weekly practice. The best gains typically come from the sections with the lowest accuracy per minute.
See how to use mock tests for MAT for a worked example. Also read the MAT pattern overview, try free MAT mock tests and browse the MAT hub.