Bitbucket CI/CD on top of Salesforce SFDX

Hi,
I am looking to enable CI/CD to live Bitbucket solution for one Repository and two sandboxes (Dev & Qa). The runners are already configured, but I need someone to walk me through the next steps.

Please let me know if you have the necessary experience in Bitbucket and SFDX to complete the process and start immediately? Please respond only if you have experience in Bitbucket CI/CD and SFDX.