rules about use of content from other website!

Hello!
I am creating my new blog with wordpress. I have succeeded in creating the structure of my new website, exactly as I liked it to be, and now I am working on writing and creating images etc.
This is the first time I create a blog so I am sorry if my question doesn’t fit the argument of this section.

QUESTION 1: could you tell me where ( on the web) I can find information about rules on using images and content from other website, please?

I would like to post some research I did in fashion design (content that I write by myself) but I would like to cite and post also my sources and some images of clothes and some video from youtube (a part of a film). How can I do this but being respectful of the owner of these pictures/ film?

I need “cheap & chic” solutions ??

QUESTION 2: how can I protect the content I post? ( I am thinking about Creative Commons license — there are better solutions? I would like to allow people use my contents but citing my blog.)
thank you very much
violante