A game engine provides general building blocks, like reports from collision detection, creating entities in a designated location and telling what object the player clicked on.

It's up to you to apply them meaningfully (e.g. spawning “the party” in or around their “command base”, or allowing the player to select units and choose targets by clicking on the map) to obtain a game. Nothing about tracking landmark ownership changes for scoring purposes stands out as backed by interesting theory or obviously complex: it's hard to give advice.

Can you think of appropriate algorithms and data structures and pursue them until you get into trouble? Can you understand and adapt basic examples of something you are doing for the first time? You are going to find advice and tutorials about specific technical issues, not about doing exactly the game you have in mind.

BNTKids-Studios said:
My former roommate and friend said I can find tutorials, tools, and the likes for almost everything. Now your telling me that I will not find tutorials for everything. Who am I supposed to believe?

I, too, am telling you you won't always find a tutorial for exactly the thing you're trying to do at the time. Your friend is not wrong, but “almost everything” certainly doesn't mean “everything and anything.”

BNTKids-Studios said:
I don't know what you mean by algorithms and data structures.

He was just asking you how skilled you are with writing code. Maybe you can manage without the necessity of a tutorial, if you're a good enough programmer.

BNTKids-Studios said:
And that bit about “Nothing about tracking landmark ownership changes for scoring purposes stands out as backed by interesting theory or obviously complex… I think you referring to intellectual property, right?

I'm pretty sure that's not what he was talking about. He was probably talking about a feature of games like Pokemon Go, using real-world landmarks as command bases.

There's no need to get your hackles up. Lorenzo was being genuinely helpful.

What I meant by “landmarks” are simply the mentioned “command bases you must take over” in the game.
Considered abstractly, this mechanic requires a limited palette of technical building blocks:

• Defining the bases as map regions and sets of objects
• Conquering or losing the bases with appropriate events (objects entering or leaving map regions, e.g. attackers and defenders, objects colliding with objects, e.g. characters reaching a flag, objects being destroyed, e.g. wall segments), queries (counting objects in a map region, e.g. invaders in the main building), timers (e.g. how long has the base been vacated by defenders)
• Keeping score with calculations over appropriate data structures (the state of each base: held by either faction, disputed, destroyed; and the ending conditions of the whole battle).

All of which seem a modest addition if you already have a working game loop and characters roaming on a map.