These two pages from OWL at Purdue University give definitive instructions for creating in-text citations and for endnotes and footnotes, MLA style.

For the serious student in grade 11 or 12, who wants to learn academic skills required in university papers:

In-Text Citations, or what is also known as Parenthetical Documentation

Here are two different sources for this. See which one you like the best.

MLA In-Text Citations

Parenthetical Documentation

MLA Endnotes and Footnotes