I'm making a TAS for SMB1 and need to get flagpole glitch to optimize the run, however I've looked up multiple tutorials that give the inputs, but they don't work for some reason.

I landed on the first pixel of the third block from the top of the staircase at the pole (while not holding B), then held B+R for 2 frames and did a full jump so that Mario was hovering 3 pixels in the pole (https://gyazo.com/3b2b224c0e4f8df671952118201eef44). I began to hold left on that frame. I held left for the next to frames, and on the third frame held L+A for one frame.

The closest Mario comes to contact with the pole: https://gyazo.com/e6c9a233e776d2ae5dc4c85274d32b40

I know that there is a TAS only version of fpg, but I can't find a video or explanation of it anywhere.

Thanks!

You're WAY better off going to TASvideos for help with TASing. A lot of people here aren't even particularly experienced at RTA speedrunning, let alone compiling a TAS.

tasvideos.org

OK thank you for the advice.