Made a summary: First, we are greeted with the main menu. You click play, then in the first stage (AKA NORMAL SCHOOLHOUSE), It is mostly the same as the Baldi's Basics we know, except it is missing all of the other characters except "Baldi". But, when you get to the 7th notebook, the YCT-pad pops up with baldi's face in the left bottom slot that shows the status of Baldi, the camera zooms in on that slot, before we get to see his whole body, but silhouetted black, on a red background. He then begins to cough, and violently transform into what the game calls "Decoy". Then, we go back to the schoolhouse, and you either get jumpscared by a weird floating face entity, or you meet said entity by leaving teh schoolhouse, either route leading to him asking you to play hide and seek with him. Upon answering yes, you are teleported back into the schoolhouse, now having to find the floating face entity 6 times while avoiding Decoy. Upon finding him on the 6th time, he congratulates you (I think, I haven't really checked that much and forgot a little), and then you are teleported to a red fleshy room, where we can see Decoy balled up, visibly distraught. The only way to progress is to get close to him from there, in which he then tries to catch you, but you fall back, and as he reaches for you again, he just disappears. Then, a cutscene plays of Decoy in a black silhouette on a red background again, reviewing his new form, before suddenly being stabbed in the head with a spear shaped object, and falling dead, then the mod ends. (He may be revived later on if more of the mod is made)
Edit: He also aggros in stage 1 after the second notebook, and that being that there is no impossible question in this supposed "prototype"