To place a like button for your facebook page
sign in to your facebook,
go to
https://developers.facebook.com/docs.../plugins/like/
put in your facebook page url and click "get code" button to get code. Simply paste the code where you want the button to appear.(widget area, header or footer)
To place a like button on each post of your blog
It depends which blogging CMS you are using. for instance you can simple install a plugin (social sharing toolkit) and use friendly plugin user interface to show a like button on each blog post.