How can I access the measurement tool, I have no top menu bar available. Is that because its free? Or because I’m using an older macbook?
It’s not because it’s free: SketchUp Make 2017 (still available, but no newer versions will appear) is free, and it has the top bar.
And it’s not because you’re on a Mac - older or newer. All downloadable versions of SketchUp on a Mac - at least 2015 and newer (I can’t make this assertion for earlier versions as I never used them) - has the top bar.
The difference is that you’re using the browser based, cloud hosted version (SketchUp Free). It, along with SketchUp Shop and SketchUp for Schools share the same interface, which is quite different from the versions that run as a Native App - SketchUp Make, SketchUp Pro. This interface difference is, I assume, because the software UI tools available within a web page are significantly different than those available to a local app.
The cloud based versions are the new kids on the block. Browser based SketchUp made it’s debut during (if I recall correctly) the opening plenary session of Basecamp 2016 in Steamboat Springs as what was essentially an open Beta of the current SketchUp Free - at the time it was called My Sketchup. It became a finished product a couple of years later, with SketchUp for Schools soon following. When the 2019 version of SketchUp (local app based versions) appeared, it became SketchUp Free - and they debuted SketchUp Shop as a cloud only, subscription based service that allows commercial use, and has some features available that aren’t in SketchUp Free.