Uploading photos from MacBook to iCloud

Hello, I am a beginner user of iCloud. I have thousands of pictures on my Photos (MacBook Pro - Mac OS Sierra) that I'm trying to sync / back up to the iCloud. From what I understand, I only need to go to System Preferences > iCloud > check Photo > check iPhoto Library, check My Photo Stream, check iCloud Photo Sharing. It seemed to upload *some* pictures to iCloud, but not all. I have been giving it a few weeks (not days), and it does not seem to move at all. I have plenty of storage space in the iCloud. Am I doing something wrong? The photos that I'm taking from my iPhone seem to be uploading fine to iCloud. Only the Photos from the MacBook is not. Any help/advice is appreciated!