What is it?
According to medical experts, social distancing is deliberately increasing the physical space between people to avoid spreading illness. Staying at least six feet away from other people lessens your chances of catching viruses like COVID-19. Examples include avoiding mass gatherings, working from home if possible, closing schools, visiting loved ones electronically instead of in person and canceling or postponing conferences or large meetings. 
How does it work?
Social Distancing slows the spread and flattens the curves of viruses by putting greater distance between poles or contacts. By isolating one’s self and doing their best to stay inside or away from general public/ large crowds, they have in essence, removed themselves as a pole that the virus can ping off of to infect more people.
Simply put, when one social distances it decreases the number of people bouncing around in the given area, drastically reducing the amount of people who 1. May catch the virus and 2. Gives longer time in between contacts so by the time an infected person makes contact with another, they might actually be non-transmittal.
The ‘Washington Post’ has a great live model of this in a recent post. See it here.
What can I still do while ‘Social Distancing’?
You can still DO a lot of things. However, it might just be accomplished slightly different or with less human interaction.
For example, eating out. You can still go out to eat, however, sitting inside the restaurant is off the table. Restaurants are offering curbside pick-up/carry out only options.
There are many things listed in this article by CNN here.