I chosed one dipole as you see below I kept the loc number one and everthing is [0;0;]:
The positions are in meters, therefore in the range of 0.01 meters. Matlab inappropriately rounds this to zero. Just don't use the Matlab variable explorer, this is a terribly inefficient way of exploring your data. Load the .mat file in your Matlab workspace with the load() command (or use the menu File > Export to Matlab) and work with it from the command line.
My question is how can I choose a dipole the located in specific areas, for example in somatosensory region?
Dipole scanning gives you the most significant dipole at each time point: 6000 time points => 6000 dipoles. You don't decide where you want the selected dipoles to be located.
Please refer to this tutorial:
https://neuroimage.usc.edu/brainstorm/Tutorials/TutDipScan#Dipole_scanning