Fix: Update content in the "Getting Started With Contributing" section and clarify the instructions to create an issue

[adiati98]

Description

This PR updates the content in the "Getting Started With Contributing" section to emphasize the importance of reading documentation and having an issue to accompany a PR.

It also clarifies the instructions to create an issue so our course participants can follow along without getting overwhelmed.

Related Tickets & Documents

Fixes #180

Mobile & Desktop Screenshots/Recordings

Steps to QA

Tier (staff will fill in)

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