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GitHub GH-900 Cheat Sheet: Basics, Collaboration, and Flow

April 24, 2026

GitHub GH-900 cheat sheet for basics, collaboration, flow, traps, and final review.

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Use this cheat sheet for GitHub Foundations after you know the vocabulary and need faster collaboration decisions. Foundations questions usually test whether you can separate Git mechanics from GitHub collaboration, pick the right workflow object, and protect a repository without overengineering it.

GH-900 answer sequence

Use this when the stem mixes Git, GitHub collaboration, repository objects, or security settings.

    flowchart TD
	  S["Scenario"] --> L["Is this local Git or GitHub collaboration?"]
	  L --> O["Identify the object: commit, branch, PR, issue, or workflow"]
	  O --> P["Choose the simplest collaboration path"]
	  P --> V["Apply the right permission or protection layer"]

Read every GitHub Foundations question in this order

  1. Decide whether the question is about local Git, hosted GitHub collaboration, repository security, or project tracking.
  2. Identify the object: commit, branch, pull request, issue, discussion, project, release, workflow, or repository setting.
  3. Choose the simplest collaboration path that preserves review, history, and ownership.
  4. Add security only at the right layer: account, organization, repository, branch, secret, or workflow.
  5. Reject answers that mix up issues, pull requests, discussions, and repository files.

Git versus GitHub

Need Git concept GitHub concept
record source change commit commit displayed in hosted repository
isolate work branch branch with PR, protection, and review
share local work remote push/pull repository collaboration and permissions
combine history merge or rebase PR merge strategy and protected-branch rules
recover history log, reflog, revert repository activity and review trail
coordinate work not Git-native issues, projects, discussions, notifications

Collaboration object chooser

Situation Use
propose code change pull request
track bug, task, or feature request issue
discuss broad idea or Q&A discussion
track planned work across issues and PRs project
group planned work by release target milestone
publish versioned software release and tag
explain repository usage README and docs

Pull request review map

Requirement Strong answer pattern
code needs peer review open PR, request reviewers, address comments
tests must pass before merge required status checks
protected main branch branch protection or ruleset
unclear proposed change PR description, linked issue, and smaller commits
conflict appears update branch and resolve conflict before merge
wrong merge style concern choose merge commit, squash, or rebase based on repository policy

Repository and permission basics

Topic Fast distinction
visibility public, private, or internal where available
collaborator access repository-level access for individuals or teams
organization access teams and roles scale better than one-off user grants
branch protection protects important branches from unsafe direct changes
CODEOWNERS routes review ownership for paths
secrets store sensitive values outside code and rotate if exposed
audit/activity use history and logs to understand what changed

Security basics

Risk Better instinct
secret committed revoke, rotate, remove, and prevent recurrence
direct push to main protect branch and require review/checks
broad repo access use least privilege and team-based access
dependency risk review alerts and updates before merge
untrusted automation check workflow permissions and secret exposure
suspicious account activity review authentication, sessions, tokens, and audit signals

Common traps

Trap Better instinct
Git equals GitHub Git is version control; GitHub adds hosted collaboration and governance
issue for code review issues track work; PRs review and merge code
discussion for private secret never put secrets in public collaboration surfaces
branch protection after incident only use protection before critical branch mistakes happen
merge without evidence reviews, checks, and linked context reduce risk
every solution is Actions many Foundations scenarios need repo settings or collaboration objects

Final 15-minute review

If the stem says… Start here
code change branch, commit, PR, review, status check, merge
work tracking issue, label, assignee, milestone, project
broad conversation discussion, not PR comments
protected workflow branch protection, required review, checks, CODEOWNERS
access problem visibility, collaborator, team, role, least privilege
exposed secret revoke, rotate, remove, prevent

Practice fit

Use IT Mastery for the exact product route, practice status, spaced review when available, and close-answer explanation practice as coverage expands.

Open the exact IT Mastery route here: Foundations on MasteryExamPrep.

One-line decision rule

GitHub Foundations answers should choose the right collaboration object, preserve reviewable history, and protect repository access without confusing Git mechanics with GitHub workflow features.

Revised on Sunday, May 10, 2026
Study Plan