Update README.md

Author: Mathdallas-code

README.md

@@ -1,2 +1,15 @@
 # Distance-Calculator
 This is a Distance Calculator I made.
+
+## How to use
+
+Simply download this code or clone it using git.
+Then, in the folder which was cloned, try any of these commands -
+
+- `python distance_calculator`
+- `python3 distance_calculator`
+- `python -m distance_calculator`
+- `python3 -m distance_calculator`
+
+I made this mainly to find issues in it.
+If you find a bug or an error, feel free to open an issue and I will solve it.