I dont understand how I try like 20 times and couldn’t get it to work. 
When i first looked at the tutorial/manual i was stuck on here too i couldnt get the cmd prompt to work as the tutorial explained. They left out the parts assuming you already know how to use cmd prompt.
So you will have to learn how to use cmd prompt first if you want to run programs from the cmd prompt, which is not on panda3d.
In cmd prompt you have to change to the proper directory of the program you want to run with the command ‘cd path-of-your-program’, then execute the program by typing the filename.
Post the whole output here. You can copy it in 2 ways, the slow and the fast one. Play around with it.
You don’t have to use command prompt if you don’t want to.