Hi I recently started speedrunning Super Mario and i want to know how to do a Fast Accel

I don't think you are ready for learning a fast accel. Your 8-4 run has a lot of slowdowns that are much easy to get rid of.

If you still want to learn in, there you go: Just follow the inputs that are described in the video.

Thank you

Be careful watching Bismuth. Its addicting. One minute you watching a short video on SMB1, the next you're binging the entire History of The a Button Challenge. Definitely not speaking from experience.

To do a fast (enough) accel, make sure you're holding B at the start...