What's on a results page
A modern SERP is more than ten blue links. Depending on the search you'll see ads at the top, an AI overview, a map pack, a "People also ask" box, images — and then the organic results. Every one of those blocks pushes the organic links further down, which is why two keywords with the same position can send very different amounts of traffic.
Why the top 10 is the goal
Click-through falls off a cliff with position: the first organic result takes a large share of all clicks, and by the bottom of page one there's little left. Page two is close to invisible — which is why "ranking" in practice means being in the top 10, and why keyword difficulty is defined as the difficulty of getting there.
Reading a SERP before you write
The results page is free competitive research. It shows what kind of pages Google wants for the keyword (the intent), who you're up against, and which blocks — ads, AI overviews, maps — will be competing with you for the click even if you rank well.