I wrote a lengthy mechanical description of the two, then realized you really care about the result, not the mechanics involved. So here is the most basic of observations for you to consider. If you want the long, technical version just ask 
On an automatic motorcycle you are stationary as long as the engine is at idle. To go you speed up the engine and there is a slight lag time or delay before you start to move. The more throttle you apply the faster the engine revs and the faster you go, until you eventually achieve the motorcycles top speed. It’s just like a snowmobile, if you have ever ridden one of those. Now that you are going fast and the engine is spinning like crazy, you might want to slow down, so you let off on the throttle and the motor slows you down rather quickly. If you are not slowing down enough you might even need to additionally apply some brakes. If you want to go faster again you need to get back on that throttle quite hard and eventually things will speed up again. With an automatic motorcycle, you better like the sound of a high revving motor, because you are going to be hearing it a lot. The connection between the engine and the rear wheel is not as positive as in a standard transmission vehicle, almost like having a big spring in there that you have to wind up to make it go.
Both automatics and standards have a clutch that uses friction to couple or decouple the spinning engine from the rear wheel. The clutch in an automatic is engaged by revving up the engine 
centrifugal force ), where on a standard the clutch is operated by your left hand lever. ( finger force 
On a motorcycle the automatic transmission has a rubber belt that will eventually need to be replaced, the standard uses gears that run in oil and the oil will need to be changed regularly.
With the Standard transmission you manually select the gear appropriate to the road speed you wish to attain, neutral goes nowhere, first gear to go slow and upwards through the gear ranges to go faster and faster. Within the operating range of each gear selected your engine speed is directly controlled by the throttle, speeding up the engine goes faster, slowing the engine goes slower and the relationship between engine speed and road speed is very direct and positive. Learning to drive a standard is undeniably harder, but there are benefits and once you have been operating standard for a while, you don’t even think about it, all the actions become very natural. ( like breathing ) Having learned to drive a standard you will be able to ride any motorcycle. Standard transmission motorcycles slightly outperform automatics in all aspects including engine longevity and fuel economy. Standards are more fun to ride.
BTW …as you might guess I’m slightly bias, but my wife and daughter both drive standard and prefer them to automatics.
