You always need an introductory sentence which ends with a colon (:).
If the text after a bullet point is a complete sentence, it should be punctuated like a normal sentence.
More help with writing.
The pronoun I is always capitalised.
More help with capitalisation.
Apostrophes are used for showing possession and short form. They are not used to show plurals.
Now do the exercise.
When two complete sentences are joined together using a conjunction (for, and, nor, but, or, yet, so), it should have a comma before it.
More help with commas.