I’m a very long time user of SU but I just moved from SU2020 Pro to SU 2023 Pro:
1.Where is the Measurement Window? How do I model to scale? My units are set…
The measurements window is where it’s been for years on the bottom right corner of the screen.
You don’t need to hold the modifier keys anymore, for making a copy with the move tool just hit once either before clicking or while you’re moving an object, if you want to copy an object several times you mis hit Ctrl twice before clicking on the object you want to clone.
That depends on the template you choose, but you can also change the units on the model info menu, you can access to it from the window menu or from the bottom right corner, there are two icons there, the left one is for geolocation and the one next to it opens the model info window.
You should read the release notes. Several versions back Move/Copy was changed so you only tap the Ctrl key to activate Copy. If you tap it twice it switches to Stamp model which then places copies of the object wherever you click.
Switch to persistent modifier (tap and release)
https://help.sketchup.com/en/release-notes/sketchup-desktop-20211
You should read through the release notes for all the versions you’ve missed as well as the current one to see what else has changed.
For the measurements box part of the problem, it is possible for a Windows application to apparently be maximized, but parts of the window are off screen. Try going out of and into maximized, see if that makes it appear.
hey,
right now we’re all spitting in the dark, could you provide a full-screen screenshot please? it’s hard to say what’s going on without looking at it 
I’m on 2024 Pro on a MacBook, and the measurements window is only visible in full-screen mode. When I’m doing Campus videos and switching back and forth, it’s awkward ti minimize and then select between Safari and SU. Is there a way to make the measurements box visible all the time? Thanks -
You have most likely enlarged the SketchUp window and then dragged it down to where the measurements box is off the bottom of the screen. To restore it, alt-click the green button on the window. That should make it take up all the free space on the screen but not really full screen.
What @slbaumgartner says… make the window smaller and you should see the bottom of the window with the instructor and measurements box.
Well, somehow clicking the green and then the green again brought it back into the window - thanks!