Hey there AppleNewbLA,
Thanks for reaching out to the Apple Support Communities.
To get started, are you viewing the available storage on your MacBook as shown in this link here: See used and available storage space on your Mac - Apple Support
If you see more than one disk in the Storage area of General 
settings, your internal disk has multiple volumes or containers. See See if your Mac shares space across APFS volumes for information about free space available in containers.
1. On your Mac, choose Apple menu 
> System Settings, then click General in the sidebar. (You may need to scroll down.)
2. Click Storage on the right, then click All Volumes.
Move the pointer over a color to see the amount of space each category uses. Light gray space represents free storage space.
As for not being able to view videos until they're downloaded from iCloud, this would be expected behavior if you have Optimize Mac Storage enabled. For more details, check out this next link here: Use iCloud Photos on Mac - Apple Support
Turn on iCloud Photos
1. In the Photos app 
on your Mac, choose Photos > Settings, then click iCloud.
2. Select the iCloud Photos checkbox.
3. Select one of the following options:
* Download Originals to this Mac: Stores the full-size versions of your photos both on your Mac and in iCloud.
* Optimize Mac Storage: Stores smaller versions of your photos on your Mac when storage space is limited, and keeps the original, full-size photos in iCloud. Choose this option to conserve space on your Mac. To restore the originals to your Mac, just select “Download Originals to this Mac.”
When you first turn on iCloud Photos, it can take a while to upload your photos to iCloud. You can continue to use Photos while your photos are being uploaded.
To have iCloud Photos sync photos to all your devices, use the same Apple ID to turn on iCloud Photos on all your devices.
Keep us updated on what you find.
Take care.
