I created an additional column using relations, by taking data from another table, in the new relation column the data appears, but why can’t I display the column in the items in the layout design ? Does it have any effect on the free package I’m using?
Depends what type of component you want to use in the layout.
Assuming something like a Title, Text or Fields component, you will need one or more Lookup columns on top of the relation to retrieve the specific values you want.