I assume that you are referring to these 2 rules that you are not sure about:
22. Advertising (this includes mining pools, gambling services, exchanges, shops, etc.) in others threads' is no longer allowed, including, but not limited to, in altcoin announcement threads. [8]
In your thread you are planning to use Coinbase as an example, but since you are the OP and not posting in someone else's thread you are not breaking this rule.
24. Advertisements (including signatures within the post area) in posts aren't allowed unless the post is in a thread you started and is really substantial and useful.
Again, the focus is that you shouldn't make any advertisements in someone else's thread. But since you are making a guide for people to read and use, the thread is both
substantial and useful . And besides, you have to use something as an example.
That is just my way of interpreting these rules and I might be wrong so lets see what others say.