Wrapping the engine modules

I''m planning a 3d engine, divided in some modules. But now i had a problem. I didn''t plan how to wrap it all together. I mean all the modules. So, now i need your opinions, how would you do so? I think i would to something like this: 1) Update ALL models (positions, collisions, ...) 2) Update the frustum based on active camera. 3) Find what octree nodes are in the frustum. 4) Render the models that are in that nodes. The engine is for a 3D 3rd person ''pseudo''RPG-action shooter. All comments will be welcome thanks PD: Can you avoid telling me things like ''how much exp do u have in programming? in engines? in blabalbla? buz that isnt what i asked :D PDD: Im spanish, so... my english isnt good