From 1 end of the arb where it passes through the tca to the other side.
Make sure the arb clamps are not tight as you may have to centralize the arb once its all in place.
Also have the car back on the ground and settled before torquing everything up,that's in the Ford manual.
Once the tca is bolted to the subframe getting the hub onto the balljoint will 've easy,just lever the tca down and centralize the hub over the balljoint then allow the tca to raise up into it.
You shouldn't have a problem once it's bolted to the subframe.