The left menu gives 5 options (four at the top of the screen and one at the bottom of the screen).
When you click on the option with the "3 horizontal lines", you can see the introduction text of Map (the one you can read in the chapter "first steps").
The small funnel, allows you to activate the filters during your search. To activate a filter, simply check the one you want (you can check several at a time). To deselect, you will have understood, you must uncheck the filter(s) that you do not want to see displayed on the map. By default, all filters are selected (you see all the dots on the map).