Load DBML from a text file

I am new to dbdiagram. I have created a simple diagram by copying and pasting dbml from a text file into the dbml editor (black area on left of the screen). I see import options from SQL etc, none of which I am familiar with. I wish to create a text file of dbml and then import it. How can I do this?

Unfortunately, we haven’t support importing DBML files yet. But don’t worry, it already in our roadmap. We will add this feature asap! Will keep you informed when it’s readied.
Thank you.