I have set up the server 2017 mirroring. And it does not have a witness server.
I have seen the below youtube video to know how to recover the DB during failover scenarios. Regarding this, I have gone through some articles too.
If you want to use the mirror database you need to have transaction log backup from the primary server. If you have multiple transaction log backups then you need to restore one by one in mirror server to activate. How to start the endpoint (mirror DB) if not able to recover transaction log backup from the primary?