I'm doing the story and Im immediately stuck in the tutorial, the guy says use your subweapon by pressing v to power the machine. Well I dont have a subweapon and i've redone the entire beggining 3 times.
What the heck do I do.
You're probably stuck there. Indeed, the guy tells you to use your subweapon... yet you don't have any if you missed a previous branch of the map.
Simply go back until you're in front of the blue haired girl and press UP to get to a branching area (you know you can do that because there's a small arrow below the ground, highlighted in red in pic for clarity).
There, go inside the building to the left (it's the only door, you can't miss it). Once inside, break the boxes on your immediate left and walk over the metal box with a dot on the ground to equip a subweapon. You will be able to change subweapon later on if you find other boxes like that. You can see which subweapon you currently have equiped at the top left corner (circled in red).
Don't forget to check the vending machine, else you'll be stuck later on. Hope that helped.