Update README.md (#2642)

Co-authored-by: Russell Dempsey <1173416+SgtPooki@users.noreply.github.com>

README.md

@@ -156,6 +156,17 @@ npm run build
 npm start
 ```
 
+> **Build Note:** `npm ci` will download the webui code to run in electron from IPFS using the [ipfs-or-gateway](https://www.npmjs.com/package/ipfs-or-gateway) npm package.  For details, see the [build process](`.github/workflows/ci.yml`) and the [webui code](https://github.com/ipfs/ipfs-webui).
+
+IPFS Desktop in itself is a simple container that makes sure Kubo and IPFS Webui can work together in a standalone fashion and has access to other os-specfic features like tray and contextual integrations.
+There are multiple ways to access IPFS Webui:
+
+- https://webui.ipfs.io/#/welcome
+- http://127.0.0.1:5001/webui (shipped with kubo)
+- IPFS Desktop itself
+
+All of these instances of IPFS Webui are the same but shipped slightly differently. The file you're seeing being downloaded is a specific release of IPFS Webui, i.e. v4.1.1 has content identifiers (CID) `bafybeiamycmd52xvg6k3nzr6z3n33de6a2teyhquhj4kspdtnvetnkrfim` which can be verified on the [IPFS Webui release page](https://github.com/ipfs/ipfs-webui/releases).
+
 ## Contribute
 
 We welcome all contributions to IPFS Desktop! The best way to get started is to check the current [open issues](https://github.com/ipfs-shipyard/ipfs-desktop/issues) (or drill down specifically for [issues labeled "help wanted"](https://github.com/ipfs-shipyard/ipfs-desktop/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22)) and find something interesting. All issues are categorized by the [standard label taxonomy](https://github.com/ipfs/community/blob/master/ISSUE_LABELS.md) used across the IPFS project, so you can also drill by topic (for example, [UX-related issues](https://github.com/ipfs-shipyard/ipfs-desktop/issues?q=is%3Aissue+is%3Aopen+label%3Atopic%2Fdesign-ux)).