diff --git a/matrix/element-web/README.md b/matrix/element-web/README.md
index 089c4f7..f403494 100644
--- a/matrix/element-web/README.md
+++ b/matrix/element-web/README.md
@@ -35,3 +35,32 @@ apt install element-web
 Configuring is done in `config.json`, see the [documentation on
 Github](https://github.com/element-hq/element-web/blob/develop/docs/config.md).
 
+The most important thing to change is the `default_server_config`. Make sure
+it's something like this:
+
+```
+"default_server_config": {
+    "m.homeserver": {
+        "base_url": "https://vm02199.procolix.com",
+        "server_name": "matrixdev.example.com"
+    },
+    "org.matrix.msc3575.proxy": {
+        "url": "https://vm02199.procolix.com"
+    },
+},
+```
+
+Of course, substitute the correct domain and server name. The `msc3575.proxy`
+is for SSS and may not be necessary. But it won't hurt, so let's just put it
+there.
+
+Element-web runs in the browser, on JavaScript. Yours truly found out that
+running [JShelter](https://jshelter.org/) throws a spanner in the works, so
+you'll have to disable it for the URL you publish Element-web.
+
+Also, Element-web is rather dependent on the version of your browser, so make
+sure you keep yours up-to-date. Debian users, who run "Firefox ESR" should
+know support for that is on a best effort basis, you might want to consider
+using the "real" Firefox. [Debian packages are
+available](https://support.mozilla.org/en-US/kb/install-firefox-linux#w_install-firefox-deb-package-for-debian-based-distributions-recommended).
+