You should ask specifically what you need help with rather than general tips on AI.

From my experience, it's important to establish what your goals are for the AI - do you need them to be smart and resourceful, dumb and lazy, somewhere in the between? What does "smart", "resourceful", "lazy", "dumb" mean in your game world? What type of tasks do you want the AI to fulfill? This all depends on the type of game you want to make.

My suggestion is to first establish the specific goals for the AI and then ask again specifically what you want to do and do not know how to do. Most things you'll need are already available online. Unless you're going for something extremely novel, Google/YouTube/Reddit is your friend.

Good luck.

AI is often the most complicated programming of a game. And RTS AI is most often the hardest type of AI. You have your work cut out for you. Figure 10 or 12 things to learn before you even start writing real RTS AI.

I'd say the most common AI/logic you'll have to be familiar with in an RTS game is the ability for your units to be able to move and avoid obstacles on your map. Collision avoidance and movement (pathfinding). You have to be able to tell units to move from point A to point B while avoiding all the "non walkable" regions of your map.

Look into algorithms such as A* pathfinding.

There will be a lot of additional aspects to your AI in your game but if you are able to have your units move around, that's a good start.

What you should do is write down all the behaviours you want your troops to have, you may need to write a different list for different units. You can put all these behaviours in a Finite State Machine(FSM) meaning you can only execute one action at a time. Then you need to decide how you want your troops to make a decision. You could use an action list you need to prioritise your actions, then when you implement it you just go down the list starting at the highest priority, you check if you can do it than if not you go on to the next action. So if you have move to goal before attack then troops will go to the goal before they attack enemies switch it around and they will attack enemies in range if they are not at their goal. You can also look into utility theory for making decisions and different kind of Goal Orientated Action Planning(GOAP). I recently read an article about action lists and is seems fairly simple, which is why I mentioned it 1st. Or you could roll your own all if statements and stuff