diff --git a/README.md b/README.md
index 16adc42..4629924 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,27 @@
-# Scratch Everywhere! Extensions
+# Scratch Everywhere! Lua Extensions
 
-A collection of extensions for Scratch Everywhere! including ports of TurboWarp
-extensions.
+A collection of Lua extensions for Scratch Everywhere!, including ports of
+TurboWarp extensions.
 
 > [!WARNING]
 > Custom extensions in Scratch Everywhere! are still in development.
+
+# Building
+
+To build a Lua extension, use
+[`seec`](https://github.com/ScratchEverywhere/seec):
+
+```bash
+seec -i /path/to/main.lua -m /path/to/meta.json -o /path/to/output.see
+```
+
+Alternatively, simply run `seec` in the directory with `main.lua` and
+`meta.json`:
+
+```bash
+cd /path/to/extension
+seec
+```
+
+Then it should be as simple as copying the `.see` file to
+`scratch-everywhere/extensions` and running Scratch Everywhere!!