Grids are representing models from the Data Model. They display the data stored in a model so it is easy to view for the application users. To keep the Back Office nice and neat, it is possible to group grids into sections.
A Grid basically is a table for data, every Grid displays the data of a single model with its properties. The table has a column for each property and for every object of the model there is a row. The columns are very customizable and you can decide which property you do and don't want to see. Every Grid has a from, with this form it is possible to see, create and edit data for the model.
It is possible to create multiple Grids of one model. This comes in handy when you need to show different data to different people. With a role-based user structure, you can hide views for a specific type of user. If you want to know more about Grids and how to create them, you should take a look at this article explaining all the settings within the Grids: Grid Reference