The guy who sprinted onto the field in the middle of Super Bowl LVI is revealing to TMZ Sports how he was able to bypass security and execute his plan ... giving a step-by-step breakdown of his stunt -- and why he did it.

20-year-old Joseph Duran says the whole idea was meant to promote his party company ... but unfortunately, his flag got caught in the wind and it was never fully exposed.

Duran says he initially got access to the stadium by working a VIP experience earlier in the day ... and ended up paying a random guy $50 for his employee lanyard to get closer to a striking point.

After surveying his options several times, Duran finally decided to jump from the second level of seating all the way down to the field ... making a mad dash and juking out security before getting tackled to the ground.

Duran says he was cuffed (rather tightly) and taken to a holding cell, but thanks to some alleged overcrowding, he was told to leave the stadium immediately.

Despite facing a serious fine for the stunt, Duran says it was worth every penny ... as he believes the whole thing has brought new eyes to his brand.