To do this, on your Timeline, go to your About section -> Work & Education, click on Edit. If you haven't already added your self-employment to your employment section, do that now. If you have a Facebook Page for your business, make that your "Employer" by starting to type the name of your Page & selecting it when it pops up. That little audience drop-down box beside Employer, make sure you select Public instead of leaving it at Friends. Make sure you click Done Editing!
On the other side of that same page, in your Contact Information -> Websites section, add your direct sales website and/or other website you personally created for your business. In the audience drop-down box right beside that, click Public instead of leaving it at Friends. Make sure you click Save!
There, you're done! Now, everyone can see you're self-employed, what services/products you can provide them, and can access your Facebook Page!