First define the floor elevations and then lay out a grid plan. Use the grid plan to locate columns and walls that will support beams and joist areas, which can also be CLT floor or roof panels. Assemble the structure level-by-level starting at the lowest level. Column and wall members on higher levels are supported by columns, walls, beams and joists on lower levels. Beams are supported by columns and other beams on same level. Joist areas are supported by beams or walls on the same level.
Finally, apply loads to the structure. Area loads are applied to joist areas; line loads to beams or walls, and point loads to beams or columns.