The modules with LGA pads are optimized for automated pick and place and reflow soldering. However they can also be manually soldered.
The recommended way is to use a solder hot plate and heat up the PCB under the module.
Soldering with solder iron is also possible. But in this case the pads on mother PCB must be longer so the reach out from the module. This way the paste on the pad can be reached with a solder iron.

Last Update: August 8, 2017