docs: Update "Let's Get Practical" and "Merge Conflicts" sections

[adiati98]

Description

This PR mainly updates:

• "Let's Get Practical" section
• "Merge Conflicts" section

It also improves and reorganize some parts of the "How to Contribute to Open Source" chapter to adjust and clarify above sections, and for better flow.

What type of PR is this? (check all applicable)

• [ ] 🍕 Feature
• [ ] 🐛 Bug Fix
• [x] 📝 Documentation Update
• [ ] 🎨 Style
• [ ] 🧑‍💻 Code Refactor
• [ ] 🔥 Performance Improvements
• [ ] ✅ Test
• [ ] 🤖 Build
• [ ] 🔁 CI
• [ ] 📦 Chore (Release)
• [ ] ⏩ Revert

Related Tickets & Documents

Closes #99

Mobile & Desktop Screenshots/Recordings

Steps to QA

Added to documentation?

• [ ] 📜 README.md
• [ ] 📓 docs.opensauced.pizza
• [ ] 🍕 dev.to/opensauced
• [ ] 📕 storybook
• [x] 🙅 no documentation needed

[optional] Are there any post-deployment tasks we need to perform?

[optional] What gif best describes this PR or how it makes you feel?

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[BekahHW]

I'd like to make sure I take a look at this in its entirety before it's merged in. I've done a quick glance but I'll get to the rest tomorrow morning.