SSD card casued major error

I just bought an SSD card that was supposed to help me speed up my MacBook 2014. The issue is, when I installed it and rebooted the system, all I am getting now is black screen. It is frozen there and even restarts won’t help. What should I do to make it functioning again? I am using Catalina OS.

Did you Installed NEW OS on the SSD?
Do you have another bootable disk in your system and if you have which one is privileged(when system starts which is firstly booted?)