Hmm, you mostly press the button in the top right to progress through turns as well as through the individual ‘decisions’ within a turn. And each decision is something like “What should this unit do?”, so it will automatically select a unit and you can instruct it by either clicking on the map to tell it where to walk/attack or with the buttons in the bottom left.
In your first turn, one of those units is a settler, which you might tell to found a city. In that case, you also have to tell the city what building to construct, for which it will bring up the city screen and then you select that in the list on the left. Well, and if you do build a city, you also have to select a technology for it to research, which brings up another screen with the possible technologies in a tree structure, where you select one technology and confirm it.

I’m sure, there’s tons of places one can get stuck on, but it is fairly linear gameplay, so don’t overthink it…

Well, if you played it a few years ago, the tutorial was also still rather sparse. That should be better now, too.