Avocados darken quickly when exposed to the air, so work quickly with the avocado has been cut.
Adding lemon juice will keep the avocado from turning brown so quickly.
Refrigerate avocados once they have been cut open.
This is a process called oxidization.
Even though the avocado is still edible, it looks disgusting.
If you do not want to use the entire avocado after you have cut it open, brush the exposed flesh with lemon juice…cover tightly with cling wrappressing it as close to the flesh as you can, and refrigerate.
As far as cutting into the avocado, hold the avocado on a cutting board and cut lengthwise around the pit. Next remove the pit. Then scoop out the flesh out by using a glass…(look it up…most useful thing I’ve found on the entire internet this entire year).