<p>I am new to php and wanted to make a blog using php where every one can see the contents posted in the site but another administrator page should be there which can edit, add or delete posts</p>

<p>How can i code a page like that? What are the logics required?</p>

There are
lots
of
tutorials
for this sort of venture
around the internet
.
I think It may be a bit too much to write in a single answer here.. You're best to choose one of these tutorials or find a book that uses building a blog as a means for learning more about PHP.