Montage editing for epileptogenicity map

Hi, I'm a new bee of Brainstorm.
After following the SEEG epileptogenicity map (EM) tutorial, I did success making the results of the EM I wanted.

Now, I am trying to calculate EM on the specific electrodes.
However, I don't know how to do this.

In the tutorial,
1st) defining the onset and baseline times from the link to raw file.
2nd) extracting the epochs of the onset and baseline
3rd) applying montage (to bipolar-2 montage)
4th) making volume/surfaces EM from 3rd data

I'm wondering what process I should go through to calculate EM for the channels I'm interested in rather than all channels.

You can check on this Walkthrough from one of our previous courses as explaining in this document:

You can replicate this complete tutorial from here:
https://neuroimage.usc.edu/brainstorm/Training#Park_City.2C_Utah_.28USA.29:_April_1st.2C_2024