Err... well, without any mentions of specific gripes or difficulties you are having... entirely seriously, actually play through with the tutorial enabled.
There are 3 different tutorial settings:
No tutorial
Moderate tutorial (ie, you've played some Civ games and want to mainly focus on what is different in Humankind)
Full tutorial (baby step you through everything like you've never played any kind of turn based 4x before)
The middle of the road tutorial does a pretty good job of highlighting and explaining systems and actions that work differently from Civ, or are just entirely not present in Civ, but doesn't hold your hand through every single basic concept that you would already be familiar with as an experienced Civ player.
EDIT: Beyond that, I guess uh... a lot of the game sub systems kind of work... similarly to a lot of Civ game mechanics, but not quite the same, in some cases, significantly differently.
For starters, your civ progresses as you unlock new ages, but your leader stays the same. NPC leaders have a set of traits that affect their demeanor in diplomacy, as well as give them varying kinds of buffs for their gameplay.
These NPCs and their traits are actually classed by the total score of their cumulative traits, basically just a few minor traits are 'easy', up to a whole lot of powerful traits as 'hard'. You can pick to play against easier or harder NPCs as you like.
You can also unlock traits for your own leader by basically doing in game achievements.
But uh yeah, get used to the idea of swapping civs situationally as your progress through ages... or you can sort of 'prestige' a civ beyond its roughly historically accurate age, if you want a buff to ... i think its your renown or fame score generation the purple one lol. In some situations, it might make more sense to continue with the unique units, buildings, and sometimes civ specific gameplay mechanics through an age.
Other stuff uh...
City planning is pretty important, Humankind uses a multi tile approach to cities, where you can plop down varying kinds of districts and unique buildings according to the terrain around the actual city center. You may have to balance between urban design/zoning that is super efficient in the short run, but actually inefficient in the medium or longer run, as well as defensive structures, which you'll may want to place on a choke point tile, even if it would be highly productive with a non military structure on it.
Human kind uses a heigh layered terrain approach, with I think 7 different heights. A height 6 tile right adjacent to a height 1 tile will have an impassable cliff on that border. I like to play with more extreme height variations so as to both make the world feel larger in that land traversal takes longer, things like mountain passes and terrain chokepoints become as relevant as they often are in the real world, and it offers more interesting battles.
Rivers are in tiles, not borders between them. This makes crossing rivers more time consuming and annoying... but plays well into the rest of the games combat systems... also, if you embark on a river tile early game, this is basically the representation of building small makeshift boats... and now you can move much faster up or down a river, which is very much in line with how many real world civilizations used rivers as basically logistics highways.
There's also a system of regions, basically. You can assign a few cities to be connected to the same major city, and then basically micromanage the entire region of cities to coordinate their production to subsidize each other, in various ways. If you do this well, you can benefit greatly, but if you either screw it up or don't take advantage of it, you can be at a comparative disadvantage to other players.
... theres a whole lot of stuff that is different than Civ games, I could type for hours lol.