Using structures in CoDeSys v2.3

I'm very new to Structured Text and dealing with user-defined data types. I've looked online and on the codesys manual, and from what i've read, it seems like this should work:

TYPE HistoryArr :
STRUCT
BaseRequested:REAL;
BaseActual:REAL;
AngleRequested:REAL;
AngleActual:REAL;
DateAndTime: DT;
END_STRUCT
END_TYPE

This is typed in the POU.
Codesys wants me to declare HistoryArr.. What type would I declare this as? eg. WORD, INT, etc

You should not put it in the POU, but in 'Data types'. Look at the bottom left, there are 4 tabs there.

thank you!