Multiple topics… Category per page?

Sorry for being thick… Are category pages a plugin, or built into WP 3.0.1?

I’m sorry, I’m still unsure of something. I understand category pages and how they work and how to change the way they display. But, I’m still unsure how to show all of the results of a single category within my desired page.
How exactly do I get the category posts to show up on the desired page? I have a blank page, that shows up on my menu. Do I leave the page blank, or do I put some code in the page to call the category?

Thanks for all of your time, I may not have explained it well. What I’m actually trying to do is have all of those category posts display on a certain page from the menu.

For example, when you click observing notes, I’d like to display the category observing notes. As it is now, it displays all categories.

Then I’d like to add another category, members articles. Make it a page on the top menu, and display all posts in the members articles category withing that page.

I followed the instructions, but now in the page I’m attempting to display the posts in, it shows my sidebar as well as other data.

Not sure what is wrong. I will leave it temporarily for troubleshooting.

Got it working. Thanks a lot!