Set Up Google Analytics and Ads Conversion Tags Across Domain and SubDomain

I have a website and have google analytics and ads set up on it (blog/landing page). However, on the website I have a subdomain which contains the application which is where conversions happen. I need you to help me properly set up tracking across the domain and subdomain.

Also google analytics is showing ads data, but not detailed bounce rates/session details, I need help with that tool.