WordPress and another php site on same server

Hi,

I plan to move my local multisite instalation to a live server but also have a another php website running from a subdirectory on the same server (account).

For instance, wordpress in root directory and php website on a subdirectory like: public_html/subdir

I have 2 domains, one for wordpress and an addon domain for the php website.

How can I set up the .htaccess file (files?) to have the 2 websites working?.
Are there any .htaccess examples that I could look into?

Thanks in advance.