Above is a video detailing one method for populating a two sided surface mount PCB. We covered using a stencil to apply solder paste for a PCB a few weeks ago. In the comments there was a debate ...

Electronics components are steadily moving away from through hole parts to using surface mount ... to help in soldering. The boards have practice “stalks” of surface mount component pads ...

They may include gas extraction systems to remove fumes from solder and work surfaces that ... are robotic machines which are used to place surface-mount devices (SMDs) onto a printed circuit board ...