Fit the intercooler to manifold last, get the manifold egr together first then put manifold bolts in and tighten them up and then do egr bolt and then go under car and do intercooler pipe /manifold join.
The bolt under car can be awkward so get a bolt the correct thread size say 4 inches long , measure threads on original bolt and then put two nuts together and weld to bolt at that length setting and then weld a handle to make a T the other end.
Then its easy to fit and push up at the same time as you get it started.
I find you also need the egr pipe in place before the manifold is in position