Normally the paste is applied by a silk screen mask so all the placements are done at the same time, the the soldering is done at the same time in an oven.
That technique in the video is basically what I do only instead of paste it put a small blob of solder on one pad. Place a resistor on it, apply an iron and position the resistor with tweezers. Then solder up the other end. That way I don't need the hot air system.
While you can pay a lot for a hot air system I did see on at a model engineering show for £40. I wish I had got that now, but hot air only comes into its own when you want to remove something from a board with more than two connectors, like transistors and ICs.