add instructions to the readme

README.md

@@ -1 +1,39 @@
 parser for the OPF PowerISA 3.1C pdf to attempt to extract all instructions' pseudo-code including subscripts/superscripts and other formatting
+
+Usage:
+* Download the OPF PowerISA 3.1C pdf (yes you need that exact version) from <https://openpower.foundation/specifications/isa/>
+* Obtain CPython 3.11 (the default `python3` in [Debian Bookworm](https://www.debian.org/releases/bookworm/))
+
+  On Debian Bookworm you can do:
+
+  ```bash
+  sudo apt update
+  sudo apt install python3-venv
+  ```
+
+* Create a venv:
+
+  ```bash
+  python3.11 -m venv --upgrade-deps path/to/your/new/.venv
+  ```
+
+* Activate the venv:
+
+  ```bash
+  . path/to/your/new/.venv/bin/activate
+  ```
+
+* Install this project in the venv:
+
+  ```bash
+  pip install -e .
+  ```
+
+* Run it:
+
+  ```bash
+  parse_powerisa_pdf path/to/downloaded/OPF_PowerISA_v3.1C.pdf > out.log
+  ```
+
+* This will spit out lots of errors and then successfully create
+  the output file -- `powerisa-instructions.xml` in the current directory.