if you are happy for the files to be on the top level folder in the project, you can just drop them all in at once on the IDE. If you want them to be in a subfolder, the best option is to:
scp -r ~/Desktop/FolderName email@example.com:Bela/projects/ProjectName
This will work out of the box for Mac and Linux. On Windows, you will need to have one of Mingw/Git bash/WSL bash and then you can do the same. I am sure there are ways to do it with
Putty as well, but I am not familiar with it. You could even use
Filezilla or similar, but - honestly - just get a terminal.