Welcome aboard and to the world of the gun club.
Please go out and purchase some "dummy rounds" for the next procedures --- for your safety of "no accidental discharge"(AD) and practice of not using live ammo.
When racking a slide, which is the term for this procedure, you hold the gun in one hand firmly and at comfortable level, with a locked arm to not move. You take other hand and pull back the slide with authority and release. Don't think about it, just do it. Let the gun do the thing in how it was built.
You also shouldn't use both hands/arms in a movement that looks like you're exercising in a back and forth motion.
Once you get comfortable with this move, it'll become very natural about where best to hold arm and hands for comfort and speed.
What I believe is happening for you is you're concentrating too much at a slow speed to make sure the round is extracted from the magazine and watching the round going into the chamber and it's hanging up on the ramp.
Anything different from what I've just described, then you need to take a picture to let us see what's happening, OR, take firearm back to dealer where bought, to have them see where the problem is and whether they/you need to return to S&W for corrections to make work under warranty.
Procedure to take gun to/into the gun store.
1: Make sure gun is unloaded/chamber is empty at home, before leaving out door. Check 2-3 times to be positive.
2: Go into gun store WITH OUT gun to let someone behind counter know you need to bring gun into store and that you're having trouble with your new gun and you need help/advice with it.
3: Let gun store employee TELL YOU how you're to bring gun into store and they know about it. Remember, they are armed, while you might not notice.
4: Hand gun to employee -- gun-butt first(barrel in your hand) or in it's gun box. They'll double check also that gun is unloaded/cleared for safety. If you have an extraction problem and there's a live round in chamber, then there's a whole other safety concern that needs addressed with handling measures.
5: Describe to them what problem(s) are. They'll usually have some dummy rounds to test with, or hand off gun to their gunsmith to check out(after filling out a form for legal temporary transfer, if takes more than a day). Don't leave without some form of receipt to show they have your gun.