Add the rear frame to the center frame using the shoulder bolt to connect the two. The bolt should be tightened to the point where you can still easily rotate the rear frame through the center frame pivot. 

Adding the rear wheel completes the rear and center assembly. 

Now we can bolt the crankset with the pedals to the front wheel. In addition, we can use the bearing holders to secure the front frame to the spindle.

Add the rear frame to the front frame by inserting the seat post through the bicycle headsets placed in the front frame. 

Add the seat to the seat post, attach the handlebars and add the bicycle brake. These are all standard bicycle parts and attach as they normally would.