You can find the mechanical package drawing in our Packaging Diagrams datasheet:
https://www.latticesemi.com/view_document?document_id=213
The package view with the pins in your design from the Lattice Diamond Project Navigator's main menu choose:
Tools -> Package view
Right click to select the option of Top or Bottom view.
The Package View can be used to assign pins, look at differiential signals, view SSO results.