What your are seeing is a sample of your data, it was fully imported but we only display to you the first 10k lines by default. You can change the sample size by clicking on "configure sample" or on the left drawer.
Not sure I understand your second question, you may want to drag the "count of records" box to the Y axis of your chart?
Some of this concepts and much more is explained in our tutorials, which I encourage you to follow: https://www.dataiku.com/learn/portals/tutorials.html