On your PC or Mac go to google.com/drive.
How to transfer files on a Chromebook
Step 1
Step 2
Log in with the same account you use on your Chromebook.
Step 3
Click on the “New” button.
Step 4
Then, select a format, like “Folder upload.”
Step 5
Select all the files you want to upload.
Step 6
Now log in to the same account on your Chromebook and all those files will be waiting for you.