How can I see my photos?

If you have iCloud Photos turned on, the photos on the device are the same as on iCloud, with the possible exception that some of them may be space-saving optimized versions if you have that option turned on. You view them in the Photos app on a Mac or on an iOS device. You can also login to icloud.com and go to the Photos app there. See: Set up and use iCloud Photos - Apple Support

If you didn't have iCloud Photos turned on but do have an iCloud backup of an iPhone or iPad, you can restore the entire device (not just the photos) from iCloud but you cannot otherwise view the contents of the backup. Restore your iPhone, iPad, or iPod touch from a backup - Apple Support