Does it matter where you put the word "not" in a sentence? Would I say I'm usually not or I'm not usually? Also, did I use the quotation marks correctly in my sentence?

Let's assume that this is the complete sentence. "I'm usually not so late." You want the "not" near the "late" since that is what it modifies.
Regarding the quotation marks. You need to put one set at the beginning of the sentence and one set at the end.
Hope this helps.

The word "not" can generally be placed in different positions within a sentence to convey different emphases or meanings. In the sentence you provided, "I'm usually not so late," the word "not" is placed near the word "late" to modify it and convey that being late is not a usual occurrence. So, in this case, the placement of "not" near "late" is appropriate.

Regarding the quotation marks, you used them correctly in your sentence. You put one set at the beginning of the sentence before "I'm" and another set at the end after "late." This indicates that the sentence is a direct quotation. Good job!

Yes, the placement of the word "not" in a sentence can affect its meaning and emphasis. The general rule is to place "not" before the word or phrase you want to negate or make negative.

In the example you provided, "I'm usually not so late," the placement of "not" before "so late" indicates that you are typically not late. However, if you were to say "I'm not usually so late," the emphasis would be on the fact that you are not frequently or normally late.

Regarding your use of quotation marks, you have used them correctly in your sentence. Quotation marks are used to indicate direct speech or to enclose a quote or passage from another source. In your sentence, the quotes are appropriate as you are indicating that the phrase "I'm usually not so late" is being mentioned.