There are a number of resources that help users understand Zcash.
The official Zcash Global community discord
Zcash Media is an independent organization that makes educational documentaries about Zcash.
Twitter is the de facto communication hub for the Zcash community, and the broader cryptocurrency as well. It's a great place to get a pulse check on all things Zcash, and also follow prominent community members. Here's a document that lists the top accounts to follow.
As mentioned in the new user guide, the Zcash forum is a great place to have long form discussions about Zcash topics and also proposed ideas. Proposals always make it to the forum so the community has a chance to discuss and debate the proposed ideas.
Z.cash is Zcash's main website. It provides content and documentation of Zcash for a wide range of users and allows new users to dive deeper into the technical explanations around Zcash.
Got coding chops and want to dive deeper into the technical side of Zcash? The Zcash Github Repo is the repository for zcashd, the first Zcash node implementation.
Another GitHub repository hosting projects of the Zcash Foundation, including zebra, a Zcash node implementation in Rust.
The concepts behind zero-knowledge proof systems.