Okay so I managed to get PrimaryPart into my Model using
local ZAP = game.ServerStorage.KEffects.ZAP
local PrimePart = game.ServerStorage.KEffects.PrimaryPart
local ClonePrimePart = PrimePart:Clone()
cloneZAP = ZAP:Clone()
cloneZAP.Parent = game.Workspace.kEffect
ClonePrimePart.Parent = game.Workspace.kEffect:WaitForChild("ZAP") --waiting for model
cloneZAP.PrimaryPart = ZAP.PrimaryPart
cloneZAP:SetPrimaryPartCFrame(CFrame.new(10,10,10))
But im still getting this error
Model:SetPrimaryCFrame() failed because no PrimaryPart has been set, or the PrimaryPart no longer exists. Please set Model.PrimaryPart before using this.
what am I missing?

2 comments
You need to set the PrimaryPart, not just add it. To do so, select the Model Object, click the "PrimaryPart" property, and then proceed to click the Instance you wish to designate.
Got it!