How do you get MacOS11 icons to stay under their assigned apps?

My laptop got fried during the freeze in Texas when my power went out in Febraury. Fried the motherboard, the battery, and the ram, computer would barely run. I had to send my laptop back to Apple to get repaired. Finally got it back and they had reformatted the computer, was expecting that, but a few of the whistles and bells I had setup are missing and I've forgotten how to set them back up. There are some icons that show up on the right side of the dock and if memory serves me correct, those icons can be "docked" within the app icon they belong to. That may not be the complete correct wording of what I want to say, but I hope you can follow along with me. I've provided a screenshot of where the icons are currently. Basically I want, let's say that Spotify icon over on the right, to stay with the actual Spotify App icon to the left of it, instead of being just a mess of icons all over the right-hand side. I'm pretty sure that's how I had it setup before my computer was formatted, maybe they were just hidden, who knows. Thanks!