You have 3 chart resolutions available to you - Daily, Weekly and Monthly. When you first open a chart, you will see a daily resolution. Each point on the graph corresponds to what is happening day by day.

If you want to get a less crowded view, left click on the Weekly Resolution button. Instead of what happens each day, you now see a chart of what happens over a full week. The Open price is the opening price at the beginning of the week, the Close price is the closing price at the end of the week while the High and Low prices are the corresponding weekly low and high prices.

As well as weekly chart, you also have a monthly chart. This will show you what happens over the course of a month and is useful for a long term view. Click on 5 or 10 year charts and you will automatically see a monthly resolution.