Ch2: How to "place"

Hi, I may have missed something. In Chapter 2, under “Adding a Sign-in Button”, the direction given in the text is to “place the sign-up button at a margin of 119 from the bottom”, but does not give direction about how to do so. Since the chapter talks about auto layout a bit and using the X/Y coordinates and such, how should this be placed? Or should I just drag it or nudge it with the arrow keys? Perhaps this was addressed in a prior section, but I’m not recalling it at the moment. Thx.

I found one option that’s mentioned a few paragraphs or so later… you can nudge with the arrows and use Alt/Option while a layer is selected to see how far one layer is from another.