Follow those steps to know this...
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How to:
i) Log on to your facebook ID and in the search box just type: "Rss"...
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ii) Now Click on the first result and you will go to "RSS Graffiti" official page and here click "Go to App"..
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iii) Now You will ask to Allow or Skip, Just click on "Allow"...
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iv) Now you will redirect on the App and Now click on "Add New Publishing Plan"...
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v) Now Choose or Write any Name you like...
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Than Click on "Create Publishing Plan"...
vi) Now You will see this wizard in front of you.
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Now on the left side click on "New Source" and Enter Your website or Blog RSS URL....
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and than click on Add Source..
Now on the right side, Click on New Target...and
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Now in the Target setup area in Choose target, choose your facebook page and in "Publish on behalf of ", choose your facebook page...
and than click "Save Changes".......
That's all..Share if You like this post....