EDIT: As the help page points out, you can do this in an even simpler way. Simply go to the HTML tab and make sure there are spaces between each paragraph, no need for the <p> and </p> tags!
Something that caused endless pain for me when it came to using WordPress (which is under the MediaFactory server for us, but uses the same text editor as WordPress) was when copying some text over to the Add Post text editor it would remove the space between paragraphs, which turns your post into one big block of text. I don’t know if there’s an automatic or more efficient way of doing this, but I know one foolproof way to ensure that the space remains between your paragraphs when copying text over to the editor. Here’s how:
When you begin to add your post, first click over to the HTML tab, circled in black above. This is where you will copy your text.
After you’ve copied your text in, it should look like the image below (with your own text of course).
Now here’s where the magic happens. At the start of each paragraph type in <p>. This little phrase tells the text editor that, “This is where the paragraph starts.”
At the end of each paragraph type </p>. This phrase tells the text editor that, “This is where the paragraph ends.”
Do this to each paragraph, and once you’re done your text should look as follows.
Do up all your categories, tags, links etc. as you normally would (making sure those <p> and </p> thingies stay in their proper places), and hit Publish! Or schedule, whatever you desire to do. Your post should now have clearly separated paragraphs, like so: