How to upload electrode locations for computing the head model

No, you do not need to import the data. However, as you mention you must have an anatomy, and the position of the electrodes with respect to it.

The steps would be:

  1. Create a new Subject and select the option Yes, use default anatomy
  2. Right-click on the Subject > New Folder
  3. Right-click on the New Condition > Use default EEG cap > ICBM152 > ANT > ANT waveguard 64 duke
  4. Right-click on the Channel file > Compute head model

Between step 3 and 4 you may want to check the number of electrodes and their labels.

The leadfield matrix would be inside the headmodel file: