Help in linking a MySQL-PHP Database from a domain to a subdomain

I am looking for a freelancer who can help me to link my MySQL-PHP database from my domain to a subdomain. I have access to both the domain and subdomain settings, and the database is already set up on the domain. I have also created a user account for the database. My Site is built with a WordPress Template which has been slightly modified

Ideal skills and experience:
- Strong knowledge of MySQL and PHP
- Experience in linking databases across domains and subdomains
- Familiarity with domain and subdomain settings
- Excellent communication skills to ensure smooth collaboration and understanding of project requirements