Promoted posts are one of the most effective ways to get new subscribers. A simple note, describing your new content channel and a simple call to action with your direct link will net you subscribers, much more so if you promote them. The more descriptive you can be, the better if promoting.
There are two ways to approach this simple tactic:
1) Copy your Direct Link and paste into your status.
IMPORTANT. If you do this process, it's important you remove the preview. Keeping the preview will trigger a Facebook error.
2) Your second option is to use Facebook's pre-built tools. Click the Get Messages button.
This will automatically pull up a dialog that links to your Direct Link, allows you to select an image and simply type your post.
Now, go ahead and boost your posts!