Imported 3 enex and how to join them as one like in EN

Operating system

Windows

Joplin version

3.5.13

Desktop version info

3.5.13

Editor

Rich Text Editor

What issue do you have?

I have wxported from Evernote and have 3 notebooks as they only allow 100 at a time.
They are in Joplin okay as 3 files.

How do I join them and name as it was one notebook before?

oz