cabin build need help

[delta1]

I am building a 18x24 cabin, with a loft, but two full stories. For the foundation I have 12-24in 3feet deep for sonotube with 24in base. They are 8ft apart except the 18ft side is equal 9. I'm on a phone so no drawing right now. I'm trying to learn about the beam system and if I need 3 2x12 or 4 nailed together and what sizes to start. I'm looking for tips, it's not permitted BUT still want it strong. I will post a drawing when I get a chance. size]

[delta1]

don't know if this will work. Trying to upload from phone.

[MountainDon]

 w*C  an not direct upload images. Images need to be hosted on a host site like Photobucket or other. Then the IMG tag from there is copied/pasted into the message here.