Set your variable then,
Enter Find Mode
set field Kandidater::ID to your variable
So not Find Matching Records?
enter find mode, set field, perform find produces a completely new found set. It operates as if you did this....
Show all records, enter find mode, set field, perform find
Find Matching Records respects the current found set where the first method does not.
An alternate solution would be a self join (two Table Occurences from the same base table) between the fields Kandidater::z_finn_Kandidate and Kandidater::Kandidate_ID
And your script would use a single step ...Go to Related Records... across the relationship using the same layout.