i bought a new macbook, how do i setup PHOTOS in macbook to download my photo from icloud

Basically,

• You have to sign in with your iCloud AppleID in Apple menu  > System Preferences and enable iCloud for Photos.
• Then launch the Photos.app. Photos will create a Photos Library in your Pictures older.

Then open the Photos Preferences (from the menu bar: Photos > Preferences) and click the iCloud tab. Enable iCloud Photos and "Download Originals". If Photos should complain, that iCloud is only available for the System Photo Library, you have first to make your Photos Library your System Photos Library in Photos > Preferences > General: Use as System Photo Library.

See this page in the Photos User Guide: Use iCloud Photos to store photos in iCloud - Apple Support

It is very normal for syncing a large number of photos to take quite a long time. I can't say exactly how long is too long, it depends. I feel confident that you have, but be sure you have enough storage to complete the task.

Set up and use iCloud Photos - Apple Support and

Use iCloud Photos to store photos in iCloud - Apple Support