As someone who's largely involved with the Pack, Matt will be reaching out to some of the werebeasts that he knows, both online and offline, to try and glean whatever information he can about the Earth Spirit's wound and whether there's anything that he should be concerned about.

He will also basically be trying to collect information from people in the Sanctuary by way of eavesdropping and getting into conversations with other staff and other Sanctuary residents - he's got this, he works there part time doing random odd jobs so he's going to come into contact with people even in passing, and he figures that some of them will spill things even if it's not on purpose. Some of the information that he's eventually going to glean is related to the black roses and the bloodied posters.

Following that, though, he's going to be bargaining for information trading online! He will mostly be found trawling supernatural-slanting Reddit equivalent forums to try and piece together all the disparate information that he's been looking for and will probably run into quite a few people there.

ETA: Depending on how much information he's found, he'll be putting it up in a post online for people to run across and spark conversation.