what i meant by using pathfinding is that you have to code the events to use it properly, once you figure out the size and spacing required for block sizes so pathfinding is working properly you need to code how units move by choosing a target position
and you can do that if im not mistaken by using the RTS example construct comes with, is very similar to the image you are showing, basically u select unit, then for that unit u can use a boolean, or variable and set it to a value =1 then if value =1 the unit will find a path to move towards the target position u give it.
the answer i gave previously was actually not broad at all, is the expectation you had that made it broad.
considering you are a 2014 construct user i was thinking you know how to code the events to achieve something like that, is rather simple, i just pointed towards the simplest solution and that is usage of the pathfinding behavior.
i think i have a tank example that does this and here it is super tank battle example
that was made with pathfinding and some tutorials from our good old C2 that explains active minimap interaction.
sadly i don't think i still have the capx for it... but pathfinding is the solution
Edited: is your lucky day i found the capx from C2 tank example update v3
however i just checked the advanced wars movement system, and it looks like grid movement + pathfinding.
and for that there are 2 Construct2 tutorials i can think might be useful for your case example 1 & pathfinding tutorial explained