Going through the privacy settings in Facebook is very easy.
You could use the privacy settings to protect my profile from either specific people , which in that case you can block people. or
you can make it private to others when people go to search for you.
If people are not specifically blocked then they will only be able to see your profile picture and page, but if you have your page completely private they wont see whats on your page , so you would have to specifically set everything up that way . In that case only Facebook friends of yours can see what you post.
There is also an option that if you would like specific friends too not see specific things then you can click on the drop down on your post and put everyone can see except , and in the except you can type in your friends names that you dont want to see the post.
Setting specific privacy settings is very important because there a lot of ways that people can access your page and get your personal information , and or use your personal information for other things ( such as cat fishing) so being extra careful with your privacy settings is very important.