Question on making trousers more fitting

Hi everyone, I’m not sure if this is the right sub for this question so I apologize if this shouldn’t be here. I’ll be glad to take it down if a mod requests it.

I bought a pair of trousers that I really like but they are way too baggy and I want them to look how they do in the picture from the website (second pic). I can’t buy the next size down because then the waistband wouldn’t fit me and the size I bought is my size. So my only solution is alter it, however I need advice on how to best do so. I’ve hemmed my own pants before but other than that I’m a total noob when it comes to sewing or alterations so I’m asking you all for help. I don’t really know how to describe what I want but I want the pants to be more fitting like in the second pic and not baggy like how they look on me. I’m going to hem them of course, but other than that I don’t know how to best go about this.