Hi Cathy!
The first thing to do is read up on our Themer’s Guide – we’ve also got a good tutorial on template overrides you might be interested in (if you haven’t already read these resources).
One approach you could try here is to modify your custom ecp-page-template.php template and add some logic at the top testing to see if a month view has been requested and, if so, loading whichever template you wish to use.
Some template tags you might be interested in here:
- tribe_is_month()
- get_template_part()
Does that help here?