Extruding a body on a angled construction plane

Followed YouTube tutorial exactly on construction planes. Don’t know why it is not working right. I created a box, added a construction plane 60 degrees to the edge of box, sketched a simple body onto construction plane and when I attempted to extrude body down to top plane of box it instead extrudes through the box. Not at all what I wanted and not what the tutorial shows should have happened. I know I must be missing something, however, have gone through tutorial at least a dozen times and still get same results. Please help.

Hi!

From what you described, I guess you want to change the mode of how extrude behaves. Here is a short video how you can change it:

Let me know if it helped or you are looking for something else.

Thank you so much !, that was what I was missing in the tutorial. It is working the way I needed it to now.

Thanks, Thanks, Thanks

Rick