Your Ceiling starts with the support system - the suspended ceiling grid. Our Ceiling Grid Installation Guide
can help you get the start you need.
Our tegular ceiling tiles have a revealed edge that "hangs" below the plane of the grid. As usual, when placing the tile into a space smaller than 2' x 2' it will require trimming; but in this case, any cut side will leave an edge that hangs below the grid. The solution is our trim strips.
This simple fix is detailed in our How To Add Trim guide.