A Microsoft file hosting and synchronization service.
Hi. I'm Brian and I'll try to help.
There are two ways. One way is to log into https://onedrive.live.com/ using your Microsoft account with the Family subscription. The other is to log into Windows using that same account and locate the OneDrive folder under your Windows profile.
Do either of those work for you? If not, describe exactly what happens when you do them and if you receive any errors messages, include them here exactly as they appear on your screen. Be sure to erase what precedes the @ if there are any addresses in the error message.