Once your study is created and delivered to teachers and then students you will want to get your ALI report. If you are using the ASSISTments subject pool you will already be receiving the report on Saturdays assuming a student participated in your study that week.
You can always request your data by using this form, you just need your email and the problem set ID. The first time you do this we will verify your email, going forward your email will be sufficient.
You may want to test out your study by assigning your problem set to yourself, working through it as a student then retrieving the data here. This will give you a good idea of how the data will look for your study.
Watch these Data Videos to help you as you attempt to understand your results.