Hello Chuck~ you can read my correction of your text below. You had minimal amount of mistakes but it is good to point them out to you so that you can learn. I hope this is going to be helpful for you.

Green - explanation

Orange - word that I believe should be in the text

Red - correction

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First notebook entry: Introducing myself

My name is Chuck Li. I come from Chaozhou, the a (you use the if you mention the city for a second time, when you introduce it you use a) beautiful city in Guangdong Province. And now I live in Shunde District, Foshan City. In my opinion, English looks like the key of the outside world. If I can learn it well, that means I can use that key to open the door, (no , in front of and) and check out see what is happening (you talk about the current ongoings/actions in the world so you have to use Present Continuous Tense) all around the world.

First notebook entry: Introducing myself

My name is Chuck Li. I come from Chaozhou, the beautiful city in Guangdong Province. And now I live in Shunde District, Foshan City. In my opinion, English looks like the key to the outside world. If I can learn it well, that means I can use the key to open the door and check out what will happen all around the world.