I figured it out for both, I had to just hold left click on a warp pipe and then click the downwards arrow then it will create another pipe both of which are linked together
and progressive power-ups, just do the same hold left click and then select the super mushroom in the menu (works only for higher tier power-ups like fire flower), you can put them into question blocks
although I cannot make a sublevel warp, I don't have a nintendo switch
last thing is why some of the text is not in English, especially in the coursebot level info view