How to use classes from another d files

[Adam D. Ruppe]

On Tuesday, 22 October 2019 at 17:34:51 UTC, Vinod K Chandran 
wrote:
> Hi all,
> I am new to D. But some fair experience with vb.net. I was 
> playing with D classes.  I wrote a class in a D file.
> The file name is "classFile.d"

did you compile with dmd -i or list both files on the dmd command 
line?