Hi Francois,
The correct conjunction approach would be to solely apply the operation:
max(pvalue)
Then keep the t-statistic and its df that corresponds to the max pvalue.
For the process panel, you can write something like:
For each value in the input file (each signal, time, and frequency):
Return the statistic that corresponds to the largest p-value (max pmap).
Note, your screenshots suggest max tmap and min pmap, but it is the other way around. The correct is max pmap and (loosely speaking) min tmap, thought the later should consider the degrees of freedom.