Hey guys! I have searched and searched for answers- not getting far. So here goes:

My org serves children and lets them work with horses. The parents of the children must fill out several forms, which are then uploaded into Salesforce for later reference on the go. Office staff typically handles this admin process, but again, everyone needs access to these files. We had been using attachments (obviously each attachment related to the child's participant record page, custom object), and those attachments were accessible to all users. It worked really well. 

Fast-forward to rolling out Lightning- I have converted notes and attachments to the enhanced notes and Salesforce files. However, nothing is shared with anyone other than me. There are THOUSANDS of these files. Without keeping the old notes and attachments related list on the page layouts, is there a quick way to share all of these files with all of our users? I can't even seem to select all and add to a library. Any information would be so very helpful!