Posting some group photos would be a great place to start.
The first question is - what is the general value level of the group? If it is largely a bunch of low value items you probably want to pull out a few of the best items and sell the rest as a lot on Craigslist or Facebook Marketplace.
So - consider breaking the group into a few subgroups such as "the good" "the okay" and "all the rest" with some assistance..