What your attorney needs to open a share
A share opens in CustodyComms, not in a web page. Your attorney installs the app, signs in at the address you shared with, and the matter appears under Sharing Matters: the timeline, the flagged incidents with their summaries, and the export. It is read-only for them, and it costs them nothing. Access does not run out on a timer; it lasts until you remove them, which you can do at any time from the same screen.