This might make things easier to explain:
not shown: 3 bolts securing fuel rail and hardlines to intake manifold. remove these, and the rail will pull the injectors out of their holes in the manifold.
pop out the injectors from the rail (thin rubber o-rings hold injectors in rails).
the isolators are thick rubber, I used motor oil. new o-rings lubed in gas, pop them into the rail first. second, lower the rail and injectors into the holes in the manifold. secure the lines/rails to the manifold with 3 bolts.