You just need to go to the Map view and in the toolbar check the "Infowindow" panel.
There, you'll see a list with your columns. You need to make sure that all are disabled.
Take into account that in the same panel there are two kinds of infowindows: click and hover, so you'll need to disable the columns in both of them.
In this tutorial you can find just the inverse scenario, where the user enables the different columns to be shown.
If you used the Custom HTML infowindows previously, click on the "Toggle fields and titles" button in order to go back to the list of columns and disable them all from there.