Yeah, if you're not used to shooting a shotgun, the first couple of boxes of shells may not be aimed real well (flinch). That's often a normal response because you think you're going to get your brains kicked out but most semi's are usually more soft shooting than their single shot counterparts.
That's why I suggest handicap/low brass shot especially at first because they don't kick as hard and they're cheaper too plus most semi's have less recoil due to how the action works. The handicap loads may or may not cycle your shotgun. Would be great if they do, but I wouldn't really expect that they will. Most semiauto shotguns won't cycle low brass. I'll mention that up front. At least not without some tweaking. But don't let that disappoint you.
This also helps you learn the "manual of arms' of how to remedy a feed or ejection failure because that is one of the harder things to learn with a semi. So, while they do have their advantages, there are some things that can make it a little harder to shoot too.
After you are comfortable shooting the gun, then pattern it at various distances. And you can also work your way up to the heavier loads once you're comfortable with it.
As for how I use a bead sight.
I had honestly never given it a whole lot of thought. I shoulder the gun and look at the front bead while ignoring the receiver altogether. I just put the bead on target and squeeze for a stationary target.
Shooting fast moving targets (like skeet or running rabbits), takes a slightly different approach because you have to aim at an even more exaggerated lead to the target. Plus, it takes some time for the pellets to reach the area where the fast moving target is going to be so you have to anticipate that. But for now, I'd concentrate on familiarizing yourself with the gun, putting some low recoil/ handicap/ low brass shells through it and eventually pattern it to see where to aim.
I generally shoot about 15 yards after familiarizing myself with the gun to start patterning there. Then every 5 yards after until I reach the point where the shot pattern (pellet count) is getting light. That gives me the idea of knowing what the maximum distance that I should pull the trigger.
And I'm not going to get into different chokes yet. Different chokes are made because they have different purposes. Ranging from improved cylinder to modified choke to extra extra full turkey chokes. But, we'll cross that bridge later if you want to.
Nothing wrong with starting out at close distances. That will be quick to show you where your point of aim/impact for your specific gun is going to be. Whether it's a little high, or low or right or left of the bullseye.