Connecting User applications to jobs. Manage them by members in a CRM like structure

Hello! I am building a website which has opportunities and then users can log in and apply to specific opportunities. The opportunities are in a database called “opportunities” and applications they make get collected in a database called “applications”. The opportunities are in a dynamic page. I wish to click on an opportunity in the backend and see the applications for that opportunity. Unfortunately I haven’t been able to figure an option or way to make it happen. I have read through several blogs and forums but still stuck. I am attaching screenshots for more information

Looking forward to some advice or suggestions. Thank you.