diff --git a/README.md b/README.md
index 4b89d06..5bc0d85 100644
--- a/README.md
+++ b/README.md
@@ -7,3 +7,106 @@
 SLS is a statically-typed, stack-based language with pure postfix notation
 combining the execution model of HP's RPL, the type system of C and Rust, and
 modern array operations from Uiua.
+
+## Build Commands
+
+**Linux**
+
+C
+```bash
+cd SLS_C
+python3 build.py build
+./bin/sls
+```
+
+Python Setup
+```bash
+cd SLS_Python
+python -m venv .venv
+source .venv/bin/activate
+pip install build wheel "setuptools>=61.0"
+pip install -e sls_build_backend
+```
+
+Python
+```
+cd SLS_Python
+source .venv/bin/activate
+python3 -m build --no-isolation
+pip install ./dist/sls_python-0.0.2a0-py3-none-any.whl
+python3 -m sls_py
+python3 -m sls_py.calc
+```
+
+Rust
+```bash
+cd SLS_Rust/sls
+cargo build
+./target/debug/sls_rs
+```
+
+**Windows**
+
+C (Using Visual Studio Developer PowerShell)
+```shell
+cd SLS_C
+python build.py build
+.\bin\sls.exe
+```
+
+Python Setup
+```bat
+cd SLS_Python
+python -m venv .venv
+.venv\Scripts\activate.bat
+pip install build wheel "setuptools>=61.0"
+pip install -e sls_build_backend
+```
+
+Python
+```bat
+cd SLS_Python
+.venv\Scripts\activate.bat
+python -m build --no-isolation
+pip install .\dist\sls_python-0.0.2a0-py3-none-any.whl
+python -m sls_py
+python -m sls_py.calc
+```
+
+Rust
+```bat
+cd SLS_Rust\sls
+cargo build
+.\target\debug\sls_rs.exe
+```
+
+**MacOS**
+
+Reference Linux build instructions.
+
+For C there is the `python build.py macos` command, but it is untested as I
+didn't test it on a Mac. I also don't know if `python build.py build` would also
+work on a Mac.
+
+Python and Rust should just be the same or similar to Linux.
+
+**RP2040**
+
+Only tested on Linux. Only SLS_C supports RP2040.
+
+Install Pico SDK to `~/pico/pico-sdk`, or set environment variable
+`PICO_SDK_PATH` to your installation path. You will also need to install the
+appropriate compiler.
+
+Debian GNU/Linux
+```bash
+sudo apt install gcc-arm-none-eabi
+```
+
+```shell
+cd SLS_C
+python build.py rp2040
+```
+
+Flash Raspberry Pi Pico:  
+Copy `.\build_pico\sls.elf.uf2` to your Pico in BOOTSEL mode