After selecting Map (Choropleth) in the Visualization Type, you will get three Control tabs to fully customize it: General, Colors, and Bounds.

In the General Tab, you can select the country column (as well as the format of its values, for example, a 2 or 3 letter ISO).

Here, you can select the Value column (according to which the countries will be painted), control the formatting of the values, and customize tooltips (when hovering over country) and popups (when clicking on country) by simple DSL:

In the Colors tab, you get to control the way countries are painted. Here, you can set Min / Max colour for painting options, and use clustered mode for adjacent countries to paint:

In the Bounds tab, you can set rectangular boundaries for a region of interest on the map, the boundaries are in format of decimal lat / lon (for example 47.3769,8.5417). The boundaries are used to "pre-zoom" on the desired area,  for convenience: