Multiple Choice columns on the Chart Dashboard have turquoise bars, you can click on the tile to expand.

When viewing a pivot chart for a multiple choice column you will see a horizontal bar chart for all the categories, with some stats on the right.

If you hover over one of the bars and select "Filter", you will add a filter for that category. You can add additional categories to your filter from the sentence bar at the top of your screen.

In the table view you will see the category per row. You can click on a category to add it as a filter.