1. How do you center an object on the document itself? My sense is it has to do with guidelines, but a) I can’t figure out how to make the guidelines visible (sometimes it works with the eyeball icon, sometimes it doesnt) and b) the guidelines, when they do show up, dont indicate the exact center line.
2. When centering two objects to each other, is there a way to indicate which object is the baseline (the location you wish the second object to be centered to)?
Regarding centering two objects, the first object placed (i.e., the furthest bacl/lowest object) is the one that is the baseline to which the other objects are aligned. You can select an object and click the ‘Geometry Tab > Arrange > Send To Back’ button to make an object the lowest/furtherst back, thus setting it as the baseline object.
As you’ve rightly guessed, centering and aligning objects on the drawing canvas relies on using Guides. Artboard does not automatically place guide lines, so if there are none yet placed and you toggle the Guides layer on you wont see any. I’m guessing this might be what you are experiencing. Turn on the Rulers in order to add and adjust Guides.
Here is the User Guide about placing guides on the drawing canvas: