My new commander !

Like the card! The activated ability seems a bit unusual, but it's appropriate for the colors of the activation cost. (I take it you're going for a 5-color identity?)

Anyway, here are some corrections to make the card fit the official templating:

1. "Caller" should be capitalized in the card's title.
2. ETB effects happen "when" a creature enters the battlefield, not "as."
3. I'm not positive, but I think "reveal X cards from the top of your library" should be "reveal the top X cards of your library."
4. There should be a comma between "library" and "where."
5. The first time you use a legendary creature's name in the card's text box, it should be the full name - after that, it should just be the first name. This means the second time you mention "Hizzy the Dragon Caller," it should be shortened to "Hizzy."
6. "Put up to 2" should be the start of a new sentence.
7. The 2 in "put up to 2" should be spelled out ("two").
8. "Dragon creature" should be "Dragon creature cards." If it isn't on the battlefield, it's a creature card; once it's on the battlefield, it's a creature.
9. Put "from among them" before "onto the battlefield.
10. In the flavor text, there should be a period after "understood."
11. Finally, there should be a new line before "- Ugin." The source of a quote is always on a new line.

(For what it's worth, as you edit the card you can see that Hizzy just wrote ~ both times. If there were a comma after "Hizzy" in the card's name, it would apply movezig's rule 5 automatically.)