Push Pull tool problems

Hello Dave, Greetings to you.
I see that you give very good explanations to people’s problems.
would you be so kind as helping me with the Push pull tool. I mainly have problems when i want to cut an opening in FLOORS because i cannot get to PUSH through it, just to pull???
Moreover i often have issues trying to type in measurements for the tape and Dimension tools ; a pop up screen says something like INVALID UNITS ??
Thank you very, very much, if you can help. I enlisted in the Sketchup community but cannot get to register my introduction of myself public? Cordially. jean-Pierre Richard

Best to start with the fundamentals course at learn.sketchup.com
The first lesson deals with that. Keep in mind that there are two way’s to create geometry, by ‘dragging’ (eg. holding the left mouse button) or clicking, than moving the other point in the direction you want and than click again to establish.
Last method is preferred, take good notion of how the dimensions are displayed in the measurements field on the bottom right, especially the ‘delimeter’ ( ‘,’ or ‘;’ )
If you’re not seeing the bottom status bar and dimensions field, maximize the SketchUp window at the top right (middle button)

If you want to introduce yourself, head for rhat topic and reply on the first post: