A lot. A whole lot. To keep it simple, let me tell you how many Earths would be needed to be put one next to another to form a chain from one end of the observable universe to the other.
That chain would be formed of 6.9 * 10^19 Earths (according to Wolfram Alpha).
That is 69,000,000,000,000,000,000 Earths. And that's just one strand. And that's just the observable universe(not the entire universe, just the one we know of). If you want to fill it, you have to cube that value.
And that is 3.3 * 10^59.
330,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Earths packed one next to another to fill the entire universe.