Using Custom Block types in layout builder

Problem/Motivation

This may be wide question, but I just want to know if the custom block types created can be used
In the layout builder (Choose a block section)

How can I create a custom block type that is not available in the custom block library in the provus layout builder?

I created the custom block and its content. It's not still visible in the layout builder browser to select it. Where all I need to modify the configs to use it?