There are a couple ways to check your grades. The first, and most simple, way is to use the "Grades" page to view a grid that lists out the courses you're enrolled in and what grades you have in each course. The second way is to use the "Progress Reports" page. This will show you more details about your grade, such as how you scored on individual assessments or standards.
The "Grades" page has a grid with each course you're graded in, and each grading period that your school uses. You can also hover over each course grade to get more details, just like you'd see on the "Progress Reports" page.
The "Progress Reports" page lets you choose one course at a time. You can view a lot of detail behind your course grade such as how you performed on certain assessments, how you performed on certain standards, or how you performed on certain grading buckets (i.e. tests, homework, classwork, etc. – these are determined by your school).
Be sure to select at least a course and a grading period (quarter, trimester, etc. – your options here are determined by your school). With these two selections, you can see grading buckets ("Assessments" and "Homework, Exit Ticket & Classwork" in the example below) and individual assessment or standard results. Use the other filters to limit results by grading system (assessments or standards), dates, scores, points dropped, etc.