To open files with a macro, I am currently using:

Workbooks.Open Filename:= "C:\file_path.xls"

How can I use a variable as part of the file path?

In other words, before I try to open the file in my VBA code I will set a
variable (let's call it date_extension). Then I want to open a file that I
know will exist with a file path whose final characters before the .xls will
be the date_extension. How can I get the file path to be recognized with the
variable?

Thanks for your help

(P.S. I am a total novice, so I may not be familiar with commands or
procedures that are fairly basic for you folks.)