All of these questions can be answered in the wiki, but here goes:
The order in which you hit the towers changes each game. To determine the order of which tower to hit with the galvaknuckles (from the wiki):
There are Mahjong tiles of different colors and sizes located
throughout the map. These tiles essentially hint in which order the
player should melee the radio tower with the Galvaknuckles (see step
8). There are eight tiles, four with Chinese symbols and four with a
different amount of dots. The Chinese symbols reflect "east", "south",
"north" and "west", and the dots tell the order each side is hit. Each
compass point and dot tile is colored, and same colored are
correlated. For example, if the player finds a green 'north' and green
three dots, the north side of the tower is hit third. This order
changes every match. If you make a mistake the radio tower will stop
glowing and won't light back up until the start of the next round. The
compass points of the tower do not change. For reference, the north
side of the tower always has a mahjong tile on the corner of the
railings.
Step 8 is to melee the tower in the determined order.
Also, it does not have to be Samuel who hits with the galvaknuckles, it can be anybody.