How to post to a Facebook page with PHP

I would like to post to my own Facebook page's wall from my website using PHP.

I have the following:

• Facebook Application with AppID, AppSecret, ApiKey
• Facebook Page with PageID
• my own Facebook account - I'm the admin and the creator of the application and page mentioned above.

E.g. I write a blog post, and I'd like to get the name, the short description and a picture on my Facebook page's wall. Or I would like to publish some articles on the Facebook page every day automatically as a cron job.

Could you provide a step-by-step tutorial how to accomplish this?

I've read this article about Facebook Login:
https://developers.facebook.com/docs/facebook-login/
but I still don't know what to write in my code.

UPDATE 1

This is how I send a request for an App Access Token:

$url = 'https://graph.facebook.com/oauth/access_token?grant_type=client_credentials&client_id='
        .Yii::app()->params['FacebookAppID']
        .'&client_secret='
        .Yii::app()->params['FacebookSecret'];

The response is similar to this (fake symbols):

access_token=326584076429|ax3-D39YbpDcR9rMRQn_fMvNu_s

What access_token is it? Application Access Token? How to get a User Access Token?

I tried to use the access token from here:
https://developers.facebook.com/tools/explorer?method=GET&path=me%2Faccounts but I got the following error message:

An active access token must be used to query information about the current user

So how should I obtain the right access token?

UPDATE 2: