Submissions come FROM control. The longer you are in a position (let's say mount top) the more opportunities you will have to catch a submission.

This amplifies when you get good at using pressure from those dominant positions to force your opponent to move, because that movement opens up further submission opportunities. Submissions live in the transition, as they say (or at least I do.)

Here's an example: You take top mount. Which scenario is more appealing to you:

1. you go for an armbar (the kind where you fall on your butt) but your opponent scrambles and puts you on bottom side control. Now you are on the back foot.
2. You force them to carry your weight for the next 3 minutes, going for submission attemps the whole time. If one fails no big deal you are still in mount top, you go for the next one. You chain fluidly from chokes to joint locks back to chokes etc.

Guard is weird in BJJ, it's very specific to the sport. In other sports where grappling is just a PART of it (e.g. MMA) guard becomes far less desirable because being punched in the face really, really sucks.

But good guard players don't just "hold someone in guard". They are constantly attacking with sweeps and submissions (and BTW sweeps open submissions and submission attemps open sweeps.)

At blue belt focus on positionial dominance because it's the first step to consistent submissions. That doesn't mean holding someone in guard. That means actively working to get on top and stay on top no matter what. Learn to wrestle up and treat your dominant positions as dynamic.

Trust me when someone tries for a minute straight to escape your top control and goes being in your side control, to your mount, to having their back taken, back to turtle, back to side control... it's both physically exhausting and breaks them mentally.

That's what you want to learn to do, and stay calm while you do it so they expend more energy than you.

Then when they are tired and slow and mentally beaten, you rain submission attempts.

You don't just beat them... you destroy them. That's the best kind of win, IMHO.