Please don't start a new topic with the same name as your previous one. So i did some edditing work
Anyway, you should select top view and place 4 nodes.
first one: anywhere
second one: Go click your first one, and then go 4 meters to the right and 4 meters down and place it.
Thrid one: Click your previous node, and then go 4 meters down and 4 meters left and place it. (this one should be 8 meters under your first one if you did it all correctly)
fourth one: Go 4 meters left, then 4 meters up and place it. Now connect the 4 nodes with H or L beams.
Now go to side view, from here it should look like ------ that. Now go to options --> preferences --> select grid tab --> and set move snap to 8 meters. Then click ok. Now click one of the nodes you see (from the previously placed square) and click 8 meters under it. Just place a node every 8 meters down. When you reach the ground, you click the next node and do it again. Until you have done em all. If it is done, set the snap to grid to 0.1 again. Now select your new placed nodes and place it under your first ones.
Now you can make 4 of these columns and connect them with X bars.
Prolly these will be pretty big, so you can decrease the sizes of what i said by 2 for example.
If you have any more questions i could make some screenshots i think. Just let me know, good luck
Greetz