How does the Amazons "+4 When Attacking" power work?
Excerpt from the rule book itself:

Amazons
Four of your Amazon tokens may only be
used for conquest, not for defense, as
indicated by the +4 on the banner itself. So
you start your initial turn with 10 Amazon
tokens (plus any additional ones that may
be granted to you by the Special Power associated with the
Amazons, depending on your combo). At the end of each of
your Troop Redeployments (see Troop Redeployment, p. 5),
remove four tokens from the map, making sure to leave at least
one Amazon token in each of your Regions if possible, and only
take these four tokens back in hand to redeploy on the map
once you Ready your Troops (see Ready your Troops, p. 6) at
the start of your next turn.