addiional info for special battles

Captain_Judo: Thanks for the feedback, Purpman. We received your team's concern by email as well.
Holakc (above) has generously written an informative guide to joining special battles. A tournament like this (Kasserine Pass Challenge) will likely feature newer teams and it's possible teams in the past have similarly dropped out because they did not correctly join the special battle. We'll remember to make this information more clear for our next challenge.