Remember that citing sources is just a convention to point your reader back to where you got ideas, facts, and quotes for your essay. It also gives credit to your sources for the help they provided in you writing your paper.
A sample MLA Works Cited page is here. That will also get you to the Online Writing Lab (OWL) at Purdue University which has a great deal of citation information as you will see by the links on the left of their site if you click through to them from here. Their site does not appear to be optimized for mobile, but it can be extremely useful from a computer or tablet.
For those of you interested, Easybib has a free mobile app. I tried it out briefly last night. It allows you to email your bibliography or upload it directly to Google Docs, even choosing what folder you want to put it in. It's pretty basic at this point, but by the time you're in college, it should have a pretty awesome feature set.
If you're concerned about plagiarism, you can find resources to help you both understand and avoid it here and here.