I have never tried push in pillars. Can someone tell me how to use them?

Mark your cake where you want them to go in and just push them straight in. Make sure they go straight in!!!! That is all you do.

It takes a bit of working to get them in straight And.......you only get ONE chance to do it right!
When I taught classes I would have them place the plate on the top of the bottom cake so the 'prongs' would mark where the pillars will go. Then put the pillars onto the plate; position over the marks and gently push down on the center of the plate until the pillars touch the board.
Another way would be to take one pillar at a time (after marking the cake they are going into) and push it into the cake ONLY about 1/2" deep - just enough that it will stand up. Now turn your cake around - all around to observe if it is straight; push another 1" and again turn that cake all around observing if it is straight; If it is not just alter the way you push the pillar; continue dooing this until it is in all the way in. Then proceed to each of the other pillars one at a time as you did the 1st one until finished.
Once push-in pillars are in the cake DO NOT remove (pull) them! This weakens the hold the cake has on them (enlarges the hole) and your seperation/support will not be stable

Are these the same as hidden pillars?

If you really want great success, get SPS. Much sturdier and more reliable. Same concept, but added features that make it foolproof. SPS instructions and what it is and where to find it can be found at the top of the How To/How Do I forum.

........Are these the same as hidden pillars?........

Push-ins are not. SPS are.

hidden pillars are straight tubes that are pushed all the way into a cake - nothing showing. push-ins are tapered and decorative w/about 2-3" above the cake w/in position.

When using hidden pillars, do you measure the height of your cake and then cut the pillars (how do you cut them) and push them in. OR do you put the pillars in the cake, mark them, take them out, cut them, and then place back in?

When using hidden pillars, do you measure the height of your cake and then cut the pillars (how do you cut them) and push them in. OR do you put the pillars in the cake, mark them, take them out, cut them, and then place back in?