The Apostrophe [ ' ] is located on the right of your keyboard, closest to your Enter key. This is usually used as a contraction for two words to become one, I.E. "You are, You're" or "Isn't, Is Not". The Accent mark [ ` ] is not a loving Apostrophe. Next, the word "I". "I" is used to refer to yourself, the speaker. I.E. "I like that." "I" Should always be capitalized in this form. Next: Your vs. You're. "You're" is a contractive word for YOU ARE. As in "You're an idiot". "Your" declares ownership of, and for someone else; "Your bike is nice". When using Quotes [ "" ], you must have a start AND end quote. Parentheses declare a side note, Brackets define a Symbol or Paraphrase, and Braces are used to define a series, sentences start with a Capital letter and end in a Period, and sentences cannot be started with a conjunction ("and") unless preceded by a semicolon or ellipsis. To top it off, quotes define a quote, and single quotes define a statement.
Finally: They're, Their, and There. "They're" is a contraction for "They Are". "Their" also declares ownership, most times plural, but often used in a case of unsure choice. I.E. "Their bikes are nice". "There" declares a location: "Over There".
People, this stuff isn't hard.