First of all, MLA, which stands for Modern Language Association, is a style guide. It is a way of formatting your papers and documenting research. It is used mostly in English and literature classes or classes in the humanities.
Secondly, since you are in a college writing class, it is not likely that you will be writing five paragraph essays. Generally, you will write an essay using as many paragraphs as you need to get your point across. It may end up being five paragraphs; it may be more. You will, of course, need an introductory paragraph and a concluding paragraph.
The thesis itself is your main idea. It is usually just one sentence and comes at the end of your intro paragraph. The points you make elaborate and explain the thesis, demonstrating your ability to make a claim and explain/defend it. Sometimes you will have three points, but you are not limited to that.
For instance, your topic may be education, and you decide to write about student debt or the high cost of college. Your thesis is your opinion about your topic, and you need to be able to expand on it. So, you could use the thesis: college should be more affordable. Then your paper would look at reasons why that's a good idea and how to go about it. This would likely require more than five paragraphs and would fulfill your paper length requirement.
Someone please help me!