How can I delete all instances with the same name?

Hello, You have to use a for loop.

local Parts = game.Workspace:WaitForChild("Model"):GetChildren()

for _, v in pairs(Parts) do
	if v.Name == "Delete" then
		v:Destroy()
	end
end

Parts is a table with everything in the Model. The for loop will go through every element in the table checking if its name is "Delete". If yes, then it will destroy the part.