Can't set up port forwarding

So recently I started making a raspberry pi web server with apache and php, and so far I could change the html file in the default debian site and make my server go online, the only problem is that I don't how to make it public.I set up port forwarding but I'm not sure that which IP should my domain name point to (my local, or my public one) and also I'm not sure i set up port forwarding right, if possible please write down the port forwarding step by step (I'm using a D-Link router). Thanks a lot.