Synology Photos

For those who migrated from Google photos or Apple iphoto, and were new to Synology photos, what process did you take with those services and your mobile phone? What I mean by that is did you just sync your phone and let synology photos do it's thing with that first? Or did you first take all of your old stuff and get that imported first? I am also not clear on if that imported data will be seperate from what you sync from your phone or not? I do fully understand that unlike Google photos, synology photos is not a mirror in that you can delete photos on your device, and there is no impact to what you have in synology photos. That seems somewhat better imo. But very interested in how you did your first setup and lessons learned.