I need a lock manager in smartthings to see who is using the lock
Look at RBoy. He has the the most comprehensive smart app there is for locks (I think).
Is it free of charge
No but the lifetime license is VERY reasonable, especially when you see some of the other DTH and Apps he has created.
Yes. I paid for lifetime as I used Blink as well so it was definitely worth it. Blink is now *$^%$&@ useless so it’s your call.