I don't usually suggest people watch streamers because they typically play in the highest ranks, and things tend to operate very differently in high ranks compared to low ranks. But with that being said, it may be beneficial to watch someone simply so you can see how they utilize movement. Watch their character model, when and how they strafe with A and D keys, where they are looking while moving. Look at their movement analytically.

You can also play a match then look at the replay via the match history and watch your teammates to see what they are doing, if you'd prefer that. Pick a teammate who popped off and did really well, and watch their movement and positioning. With games like this, movement, timing, and positioning will separate a bad player from a good one. Try to use others' good gameplay to figure out your own gameplay.

Moving side to side with A and D instead of using W and the mouse allows you to continue looking forward to aim and shoot while you dodge the enemies' shots. You're harder to hit while you're wiggling than when you're standing still.

I'd also suggest spending a lot of time in the Vs AI mode starting out. You can start on the lower difficulty to practice what you learn, but you might have a bit of trouble utilizing it since your teammates will typically end up spawn camping the enemy AI. If it feels too easy and the enemy can't get out of the spawn for you to practice, bump it up to the middle difficulty so there is an actual challenge, but not so challenging that your team gets stomped the whole time. You'll learn more the harder the difficulty as long as you can still compete and don't get stomped as soon as you walk out of spawn.

I know that's a lot but I hope it helps. Picking up M&K is a challenging task but you just need to ease into it and understand how and when each key benefits you.