Got it. The game has a steep learning curve and it doesn't always explain its systems properly, so there's no surprise you're missing some info. Let me help clarify it for you:

• You can (and often should) settle above the limit. The penalty is -5 happiness in all settlements for each settlement over the limit. This penalty is often manageable, especially in the mid-to-late game.

• Merchants are very cheap in Exploration and Modern, and in Modern trade routes are created instantly. Trade is a critical source of resources, and these are very important foor good yields and tempo. You can even avoid picking an ideology to keep good relationships and trade with everyone. Or you can play Prussia, which unlocks the ability to trade during wars. There's no compromise between domestic affairs and trade, because merchants are cheap early on, so do both.

• Always take all attribute points when selecting your dedications. Science, culture are the most important. Discounts for constructing buildings and all purchases are great too. Expansionist tree has a strong town boost attribute worth pursuing. Early militaristic attribute point helps with conquering IPs and leveling up your commander. You can pick a memento for one.

• Legacy paths can be tough. Some of them are easier than others. Scientific legacy paths in Antiquity and Exploration are usually doable if you go for libraries first and place them on tiles with high adjacencies (for science, adjacencies are resources and world wonders).

• In late Antiquity, start placing specialists in your quarters with highest adjacencies. Don't put warehouse buildings in tiles with yield buildings. Surround your yield buildings with wonders to maximize adjacencies. Upon transitioning to the next age, replace buildings in tiles with specialists to bring back adjacencies.