I recommend checking online for videos and forums to assist you in setting the sight for your rifle. With each rifle and barrell, it will differ on how the sight is set and someone with more knowledge may be able to assist you.
The same as you would any other rifle.
To sight in a rifle without shooting, you can use a bore sighting tool or a laser boresighter. These tools help align the rifle's sights with the barrel, ensuring accuracy when you do eventually shoot.
Look at gunparts.com or Numrich arms
Sometimes it on the top of the barrel near the rear sight. Sometimes it's on the side of the barrel.
The rear sight must move in the direction you want the point of impact to move. The front sight can be moved in the opposite direction.
Blade type mounted on a dovetail cut in the barrel
"IF" it's on the rifle it will be on the left side of the barrel just below the rear sight. However it may not be on the rifle at all.
S-130 is a type of rear sight used on Mossberg rifles- but not the model of the rifle. Take a look on the barrel.
This BB rifle is made by Daisy. The number will be on the barrel in front of the rear sight.
The sights are dovetailed into the barrel, you can get them out using a brass drift pin.But you run less of a chance of causing damage to the rifle and sight if you use the tool.
Laser sight is a small visible-light or infra-red laser used to enhance the targeting of weapon systems. It can for example be mounted parallel to the barrel of a handgun or rifle.
You are looking for the "sight picture". that is formed when you align the rear sight with the front sight and the target. Here is how to find it. At the very end of the barrel on top is the front sight. About 2/3 of the way back and still on top is the rear sight. If you hold the rifle stock to your shoulder and support the front of the weapon with one hand you can look down the barrel. You will notice the rear sight looks something like a V and the front sight will look like a dot. If you move the rifle so that the dot appears to be in the middle of that V you have accomplished your initial "sight picture". Now keeping the dot in the center of the V align that with the target you wish to hit. This is your complete sight picture. It will take practice to figure out if the wind is affecting you and distance to the target and a lot of other things but that is the correct way to sight the rifle in and should get you started. Good luck.