re: I can’t seem to find card.php
For cMap, the file path will be:
This is a cMap template file, not a WordPress theme file which is why you can not find it in the theme.
re: do you have any wordpress template that you recommend to use with Connections using cMap
For the most part, you can use any WordPress theme you want. Just make sure it is current and well supported. In general, in well supported current themes the worst that ever happens is minor CSS conflicts which are for the most part easily resolved.
Hope this answers your questions.