Query editor add custom column

Hi all,

a potentially simple thing :smileyhappy:

I have to add an extra column to my table - which is the copy of an existing column in the same table, but I have to change just a few values (actually names) here and there. The 'Create column from examples' seems not to be working since does not get the logic, so I am trying with the customized column. 

What I would need is the equivalent of simple "IF" excel formula which would allow me to replace the names I want to.

Example: I have a list of countries (column1) and a list of continents (column2).

I have to create a new column which replicates the continents list I have already, but includes another continent ("newcontinent") - which I would refer to some of the countries in the countries list.

So in excel woul be something like = IF ('Country'='XX'; "newcontinent"; "Country")

Any hint on how to transpose this into the power query editor?

Many thanks!!