"What are the white things?"
You have aphids! Aphids are tiny insects that almost look like little white spiders. These bugs have little needle-like mouths that are almost invisible to the eye and they suck the juices from the foliage of the leaves. Typically the damage they cause is little to none. However, when the infestations rise, they can introduce viruses and diseases and even disrupt the natural growth hormones within the leaves of our plants which can possibly lead to the death of your plant. You can tell when growth hormones have been disrupted if, after you get rid of the infestation, there is discoloration where the bugs have been.
The white bug on your plant is actually the outer shell of an aphid. As nymphs or young aphids grow they do something called molting. Molting is the process of shedding skin so the animal can grow larger and into its next stage of life, just like a snake.
Start by simply wetting your thumb with water, Safer Soap, or diluted dish soap and swipe those pests away. Now go in with your Safer Soap and spray your plant with a good coat on the fronts and backs of your leaf. After spraying keep your plant in complete shade until the spray has dried to prevent sunburn. If the plants foliage is coated with wet spray and is in the sun, it can lead to sunburn. Now watch the plant over the next few days checking to see if the bugs have gone and passed.
Sometimes the infestation can still remain after treating it. That is the case with aphids because they reproduce a-sexually and fast! This means even if there is one bug left the infestation will continue. If the infestation just seems to be getting larger, go in with neem oil, an organic pesticide derived from the seed of the neem tree. This is a bit stronger of a spray and should be used with caution. If you use neem oil too often it can kill the beneficial bacteria and bugs within the soil and plant.
Good luck, and Enjoy!