Add cd direction

[markwingerd]

The directions are well written. I followed them to the T and got stuck because it never mentioned to cd into the directory. It took me an embarrassingly long time to figure out what the problem was

Description

Added a single bullet point to the How to Contribute section

Types of changes

• [x] Bug fix or improving code quality
• [ ] New language
• [ ] New feature

Checklist:

• [x] My code follows the code style of this project.
• [x] I have updated the documentation accordingly.