What I heard was an average of 5 day incubation period (rarely up to 2 weeks). But early symptoms are often things like slight sore throat or mild fever or a slight cough, which might be easily confused for other respiratory viruses or seasonal allergies. People with minor symptoms are told to stay home and not tested in many places.

People often start experiencing more serious symptoms 1 or 1.5 weeks after symptom onset. Then getting a test result can take another 0.5–1.5 weeks.

Deaths are typically not occurring until something like 3–4 weeks after initial infection. Then in some cases data about deaths can take at least a few days to be aggregated in regional/national statistics.

So any public health measure instituted today will take at least 2 weeks to show up in the data about number of cases, and at least 3 weeks to show up in the data about deaths. Full effect of public health interventions is probably not seen in the data until a month or more later.

And keep in mind that public health interventions are only as effective as the public’s willingness to follow them. If someone is getting their news from a source which repeatedly claims that this is all overhyped and there’s nothing to worry about, they might not take appropriate personal action.