How do you know that the sights are set properly? It is very easy, you look at them. If possible you fire a couple of rounds to verify, but the AK is a "combat rifle". It is expected to be placed in situations where one will eventually be forced to pick up a rifle lying on the ground and use it immediately.
What you are doing, picking it up off the ground and putting it into service, is exactly what it was designed for. It is as if the soviets were designing the perfect prepper rifle.
First, look at the front sight. With the firearm safe and cleared look at the front sight from the muzzle. Just below the protective sight globe is a 'view port. The sight post has an index mark and the mount has an index notch. The two should be lined up. That is pretty good insurance the horizontal is set on the rifle.
The front sight will seldom be off unless the weapon has been run over by a 5 ton truck. If you ever need to move the post you will find it requires steady nerves, a good anvil and a BFH.
If the front sight meets your approval flip the rifle around and look at the rear sight. It is a simple blade with an elevator using a notch for the aiming point, just like most air-rifles, BB guns or commercial .22 rifles.
The elevator is our concern here. Look at the sight from the top. You will see a series of numbers from 0-10.
!! PLACE THE INDEX SELECTOR AT THE 0 MARK !!
The elevator is designed so that with the index at the 0, or very first position, the rifle is in a condition called "battle sight zero". You do not have to hold over, or allow for drop, from the muzzle out to 250M at this setting.
Technically, at this setting, the rifle is dead on at 200M, 1.5" high at 100M and 6" low at 250M.
In other words, if you see a deer and it is between the muzzle and 250M you will kill that deer!
If you have arranged your defensive position properly, and have range markers positioned out from your firing positions, you might want to move the selector up or down if you know the specific range and need to shoot at a range farther than 250M. (keep in mind that the drop is 24" between 250m and 300M [400M+ you do not want to know] so eliminate the guesswork or pass up the shot)
As a general rule, the elevator in the 0 position is the best idea. That is why that position is present.
Always remember that the Soviets developed this weapon while WW2 was still in progress, and the people that developed it had seen combat. They had taken weapons off dead bodies, or dug them out of rubble piles and placed the weapon in immediate use. They had slogged through mud, snow and dust so thick one could not breathe and expected their weapons to hold up to abuse, neglect and the elements.
In 1946, when the prototype was submitted, the greatest SHTF episode in world history was a fresh experience. 40,000,000 (that's forty million) Russians had died in that struggle.
Their goal was to design the perfect SHTF weapon.
One other consideration needs to be mentioned. That is recoil. The rifle does "kick", but it is not a painful experience.
I would equate the recoil to that of a .410 shotgun. Hardly excessive by any measure.
For the complete non-shooter that recoil impulse equates roughly to being head butted in the shoulder by a 4 month old baby.
Anyone weighing more than 80 pounds will not find the recoil oppressive. That puts the rifle within the capabilities of anyone 12 years old or older, even into the elderly years.
The rifle was also developed for use with heavy padded clothing for the Russian winters. Coincidentally that makes the short stock perfect for smaller people.