How to link custom data to table?

Stefano_Mazzocca

I need to build a table like this:

"Date" is an incremental date, every day there is a new value

"Control Name" is a custom text of 2 or more possible values

"Num of lines with error" is a metric that counts unwanted values in Birth Date field

I start with a simple table with all possible dates:

I add a dummy column:

I upload a custom excel:

Now I want to join my excel with the Link_Str of my table but it seems not possible:

If I first select the righter field I can reach the Link_Str column but when I click OK is like nothing was saved:

What could be a possible solution?