Manual is better, but still not perfect
One of the drawbacks of the help feature is that it is sort of hit-or-miss with the information it gives. The manual alignment tool is mentioned in a pithy sentence containing a hotlink that activates the tool. The problem is that the icon and/or function required to access the tool are not given anywhere that I could find. I have you covered, though. It's found under "Frame -> Align to previous...". You can also simply press Ctrl-A.