I think Luiz gave a pretty good answer. I’m not sure of all the grammar rules, because I am a native English (US) speaker, and only go by what sounds right, just like native speaker of any language. But, second language learners need rules to apply to put words together to communicate. Hence, Luiz’s explanation makes relatively good sense. But, in the sentences you gave you could switch up the “someone” with “anyone” and either sentence would still be okay. I doubt any native speaker would even notice the difference, quite frankly. But again, Luiz is quite right. You can’t use “someone” in a sentence with a negative like, “I didn’t see someone at the party.” That clearly won’t work and you’d have to use “anyone” there.

Someone = some person; an unspecified or unknown person. Anyone = any person; a person of any importance. Here is the difference: *You use 'someone' to refer to a person without saying who you mean. E.g.: ''He asked someone about the party.'' *You don't usually use 'someone' as part of the object of a negative sentence. In this case, you must use 'anyone', for example: ''There wasn't anyone home.'' or ''I don't know anyone who lives abroad.'' *As for questions, you can use 'someone' or 'anyone' as part of the object. You should use 'someone' when you are expecting the answer 'yes'. For example, if you think that a person met someone, you might ask: ''Did you meet someone at the party yesterday?'' On the other hand, if you do not know whether I met someone or not, you would ask ''Did you meet anyone at the party yesterday?'' Hope that helps!

ok,the first my English is not good either and I think these sentence's mistake are "someone"usually use in declarative sentences "anyone"use in questions or negative sentences

Using Google is a great tool... https://ell.stackexchange.com/questions/16132/anyone-vs-someone-which-one