docs(examples): add missing step for building at repository root first

[curtgrimes]

Description

This adds a step to some of the example README files for installing dependencies and building at the repository root first.

Fixes #513.

Additional context

I was running into the same issue as #513 because I was following the instructions exactly, not realizing that I needed to first install dependencies and build at the repository root.

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What is the purpose of this pull request?

• [ ] Bug fix
• [ ] New Feature
• [x] Documentation update
• [ ] Other

Before submitting the PR, please make sure you do the following

• [x] Read the Code of Conduct and follow the Commit Convention guidelines.
• [x] Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• [x] Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• [x] Ideally, include relevant tests that fail without this PR but pass with it.

[flyfishzy]

Thanks for the PR. The documentation is really detailed, great work!