the easyest way is to install an addon , look for the tools forum and then BOB.
the harder way is to take your time and look at the legend. The centre picture holds all kinds or one way arrows and red lines. the one way arrows, you can attack one way.. the red lines indicate points you can attack and be attacked from.
the base (blue or red) allow you to attack in the side panels. they give specific bonussess. so take a minute to read how.
then there are complicated bombard positions. again it is writen down in the legend, but it takes a while to get your head around it. it also states how you get on specific locations you cannot attack directly( see the red lines, thats now all the attack lines)
in short, its a very complicated map, but for one the legend is pretty inclusive... bob just draws you a better picture on what does what...