Each frame requires 3 connectors, top, middle & bottom.
To connect 2 end frames, use the heavier connector top and bottom, the lighter duty connector for the 2 middle shelves.
If you are adding an add-on put the 2 heavy connectors on the T-Posts and then add the next frame.
Again the frames only need 3 heavy connectors and the middle one does not support a shelf.
Once your at this point build from the bottom up, put the heavy connector in on the bottom then put the wood in. Next put the lighter duty connector in and then the wood etc...