The thing with this system in particular is that you have to solder several pieces of the LSM9DS1 sensor which comes in a nasty LGA24 (3.5 x 3mm) package. So the precautions that are common to any homemade SMD soldering process have to be increased.
For that particular piece the use of a stencil is almost mandatory, and since you would probably have to solder around 15 units making one whorts the effort.
The solder paste used has to be as fine grained as possible (type 4 or 5). I once wrote this which has some insights about the solderpaste I use.
The other components can be soldered with an iron, but the LGA has the pads hidden underneath. You have to solder it with hot air. Since you will have to repeat the operation using an oven is a good idea, it allows to do several units at the same time
And patience, lots of.. if it is the first time you try it be prepared to have a high fail rate. So purchase some spare components and PCBs