How I can see my photos on iCloud Photo Library

iCloud Photo Library is a syncing service. If you have it turned on, the photos on your device and on iCloud should be the same (although the ones on your device may be smaller optimized versions in some cases if you also have the Optimize iPhone Storage option turned on). You view the photos via the Photos app on your device. You can also use an internet browser on a computer and log in to www.icloud.com and go to the Photos app there.

More information: iCloud Photo Library - Apple Support