You have a Classic license, you don’t have to sign in. In the SketchUp Welcome screen click on License in the bottom left, then make sure that Classic is underlined (not Subscription). If it says No classic license found, click on Add License, and enter your license details.
I just sent your license to your email address, to make sure you have it handy.
Layout keeps telling me I need to update, but the popup doesn’t stay long enough for me to click on it. So I clicked on “check for updates” in layout and that took me on this crazy trip. I “think” Sketchup is up to date, how to I update Layout?
and when given a choice of Run or Save, choose Save. When it is downloaded, open File Explorer in Windows and go to your Downloads folder. In there will be SketchUpPro-2019-en.exe. Right-click on that and choose Run as Administrator.
You may see options for uninstall or repair, choose repair. When it is done, try SketchUp first and check for updates, then do the same again with LayOut.