Where can I find the photos autosynced by Google?
You should be able to find them here. If they are not there then your phone is probably not actually uploading them.

If it's not uploading photos check that in Settings > Accounts > Google > "your account" > Google Photos is checked. Also check in Google+ > Settings > Auto-backup that it is configured to upload, there are also some settings to control when (on wifi/charging etc).