I am trying to extract a time difference (in minutes) between 2 events.

These times are presently recorded in 4 columns, both events respectively in
types dd/mm/yyyy and hh:mm. I am trying to fuse this data into two columns of
type dd/mm/yyyy hh:mm such that I may use a simple substraction as shown in
the help file "Calculate the difference between two times".

I tried using the Concatenate function, but I've remained unsuccessful. Any
tips?