You respond to an invitation to a shared folder the same way you do for workspace invitations: you receive a message with options to accept or decline the invitation. See Responding to a workspace invitation for details.
However, unlike with workspaces, the content data in a shared folder is NOT automatically downloaded from the inviter's computer after you accept the invitation. Instead, you must first specify options for how to download this data as described below.
Downloading the content data in a shared folder
When you first navigate to a shared folder, you are prompted to create or select a folder in your Windows system to be shared with other members of the shared folder.
Additionally, you are prompted to specify an initial download setting: Fetch everything (automatic download) or Only fetch links to remote files (manual download on demand). If you opt to fetch everything, all data content in the shared folder is downloaded immediately, provided that another member who has the content is online. If you opt to only fetch links to remote files, the shared folder will list links to data files and you can download them later, on demand. You can change download settings at any time in folder properties.
Note: The default download option you see varies depending on the initial contents of the shared folder. If the shared folder contains at least 100 files, or any one file that is 100MB or larger, then manual download is presented as the suggested default option.