Hello and welcome 👋
It's always unfortunate when we don't remember lock screens. There's just too many passwords to remember these days 🙃
But, you can hook up the phone to PC/Laptop via charging cable and try boot into recovery mode by doing below
Press and hold volume down + power for about 15 seconds
When phone goes off quickly change button combination to below
Volume up and power again for about 15 seconds and release when you see Samsung logo
If boots into recovery mode... use volume down button to select "factory reset" then press power button to confirm
You'll be asked to confirm you want to do this so use volume down to confirm yes/factory reset then power button to confirm it
If done correctly, you'll be then asked to "reboot system now." Press pow3r button to confirm.
WARNING: You'll need to know your Google account details, you used on the phone, and enter them on set up page to be able to set the phone up again
If this helps or if you have any questions please let us know 🙃
