It's spreading like wildfire, and we probably are mostly underestimating how far it has spread already. Here's an article with really, really scary numbers regarding this.
The gist of it: There's a point at which you cannot stop the spread of the disease, you can only slow it down in hopes of keeping the healthcare system from teetering over the edge of the abyss - because if that happens, mortality rate will shoot up, due to lack of medical staff, machines (such as respiratory machines), and medicines.
The measures necessary to slow down the epidemic have to be more drastic the later they are applied, and the earlier everyone acts, the faster the danger will be lessened. It's the "flattening of the curve" that gets mentioned again and again.
We are in all of Europe most probably already well past the point where the epidemic is stoppable, so our best chance collectively is to slow it down as much and as fast as we can. Which means cutting down on social stuff - which means no large gatherings, obviously; as little travel as possible, and staying at home if you can. Home office gets an option discussed more widely, and more often.
Humans are social animals, and we all need human-to-human interaction for our sanity. It's weird, in some way, to be aware of how important contact to other people is, and usually getting told that it is healthy to have a good number of friends and acquaintances to meet with - and now, basically, what we need to stay healthy, and to lessen the danger to the more vulnerable among us, is to keep away from other people. Social distancing, if you want to use a fancier term.
In the federal state of Bavaria, all schools and kindergardens and similar childcare institutions will stay closed from today on. Universities have been closed for a few days already, the start of the semester has been postponed, and all public gatherings are off until at least mid-April, but it looks like that might be extended. Non-essential shops are probably going to be closed from Tuesday on, as well as restaurants, clubs, and swimming pools (and, I suppose, gyms etcetera).
There's no complete lockdown on everything yet here, but it will certainly become worse than now before it becomes better.
If you're in a country that is not as badly affected yet - don't make our mistake and wait until things start to get out of hand. Take precautions (which does not mean hoarding stuff!), wash your hands, look into the possibility to work from home, and do your thing to help slow the spread. This mostly means: social distancing. Whether or not you have pre-existing health conditions, it certainly will be a smart thing to stay at home if you can, and away from other people if you have to go out. It's not just your own health - it's also the necessity to slow down the spread. Also make sure to tell your loved ones, especially if they are among the higher-risk group.
If you do go out, or meet friends and family members, take care and be safe. Wash your hands, don't touch your face, don't hug random strangers, and, again, don't panic-buy and hog hand sanitizers or face masks, they are needed elsewhere - like in hospitals and doctor's offices. (Or toilet paper. Or... dry yeast? Apparently, once a supply seems to run low, people panic and start to buy more of it, until it's all gone.)
By the way, people here are joking that when in quarantine, Germans will eat only pasta, shit an enormous lot and occasionally roll themselves in flour - because the most common suspects for "Hamsterkäufe", the German term for panic buying, are loo rolls, pasta, and flour. And on Friday, my aunt told me that the patron saint of protection against epidemics is called... St Corona. I'm still not over the funniness of this. (Wikipedia only tells about this in German, not in the English version.)
So. Stay safe, stay healthy, and make sure your loved ones do, too. Don't panic - but don't ignore the danger either. We'll all know in a few weeks whether what we did was enough or wasn't - and I do hope that it will be the former. After all, Pandemic is only a good thing if it's the board game, and even that is no fun if the cards are against you, and you lose... which can happen, if you are just a little bit unlucky.
Oh, and should you need something more medieval to time washing your hands than the old "sing Happy Birthday twice" - a single stanza of the Nibelungenlied should take you safely across the 20 seconds: