Question on Sapscipt and Structures

Dear All,

I am not very familiar wtih sapscripts. When I look into the codes for the script, I find that the sapscript is able to access data from structures like VBDKR etc using

&VBDKR-VBTYP&.

Where in the sapscript do I specify which stuctures to read from and how are the data populated into the structures?

Best Regards,

Junwen