minor refactoring

Spr24/HW/Homework3/README.md

@@ -1 +1,12 @@
-[Homework link](https://docs.google.com/document/d/14rkTShnErNoh0DLebtplGDpJK5Frzv0InnWHr2vlfJY/edit?usp=sharing)
+# Homework 3
+
+[Homework link](https://docs.google.com/document/d/14rkTShnErNoh0DLebtplGDpJK5Frzv0InnWHr2vlfJY/edit?usp=sharing)
+
+---
+
+Note that question 3 does not have an input/output file. Instead, it has a testing code file that runs some tests.
+You can run the test by running the following command in the terminal:
+
+```smlnj test_parse.sml```
+
+You may notice that the first line in the test file is `use "hw3_q3.sml"`, which means that your solution file must be accessible in the working directory. If you have your solution in a different directory, you can change the path in the test file.