Acumos uses Gerrit for code reviews - https://gerrit.acumos.org. If you are unfamiliar with Gerrit or need a refresher, here are some great tutorials:
The above tutorials and more are from the Gerrit Code Review for Git documentation site.
One of the best ways to start contributing to a project is by doing code reviews. You learn the code base, and you begin to build trust with your fellow contributors. You don't need to be a good developer to review code, but you do need to be a good human being. This is a community that uses English for written and verbal communication. Contributor's English skills are at different levels, so patience and clear, concise feedback are very important for maintaining good community relationships! If you show yourself as thoughtful, polite, and diligent through your code reviews, other reviewers will be more likely to prioritize your patches and collaborate on your ideas. To borrow a phrase from Mark McLoughlin, you need to know when to be empathetic, when to be pragmatic, and when to be dogmatic. A good code reviewer focuses both on the big picture and the little details.
A "drive by" review is a +1 with no comment from a new reviewer. Those people may be looking to increase their review statistics to please their bosses. It's better to leave a +1 with a comment that shows you actually read the code and thought about it. You can also +1 and ask a question about the code.