Bulk upload files
Can we bulk upload files in project library?
Yes, you can just in project overview upload a zip you e.g. downloaded from thingiverse and it makes it a project.
But you can't bulk add files to an existing project
No. this is currently not pussible. But if you want to group projects, you can create folders and store those projects there.
As a workaround if you want to add multiple files you can export the project by clicking "Download all files", remove the project, add the new files in the zip archive and import it again.