I made this backpack that i wanted to stick on the back of all characters in the game from the start. How would i do this.
You can do that by creating a weld and changing the CFrame of the Backpacks PrimaryPart.
You could create a weld. You didn't exactly provide that much information, although I'm going to assume your backpack is a model. I'm also assuming that you're moving the model into the player's character. This script would be put inside of the model:
-- Backpack model should be inside of the player's character for i,v in pairs(script.Parent:GetChildren()) do -- Creates a for i,v in pairs() loop if v.ClassName ~= "Script" then -- Checks to see if the current item is not a script local weld = Instance.new("Weld", v) -- Creates a new 'Weld' instance weld.Name = "Weld" -- Names the weld to 'Weld' weld.Part0 = script.Parent.Parent.Torso -- Sets Part0 of the weld to the torso weld.Part1 = v -- Sets Part1 of the weld to the current item in the for loop weld.C0 = script.Parent.Parent.Torso.CFrame:inverse() -- Sets C0 to the CFrame inverse of the torso weld.C1 = v.CFrame:inverse() -- Sets C1 to the item's CFrame inverse end end