Well you need an idea of exactly what you're going to create. Then you need someone to write it for you in or PHP (although there are more, i.e. ASP.NET etc.). You need to create some databases and get to work programming aha, start with some really simple tutorials.
I am suggesting a beginners tutorial, because I assume you know very little or nothing about PHP development. I assume that because any other semi-intelligent life form would have seen a white box at the top of this page, and guess what? You can type something in it and it shows you stuff related what you typed! Amazing! And if that doesn't work, theres this cool thing, it's called a search engine, and it's got even more stuff for you!
Ok I'm board of being sarcastic, show us you've made an effort or you won't get us wasting our time on someone who could've tried themselves.
want to ask What are requirments to make a portal system?
impossible to say based on your question. What are your customer's requirements? You cant expect to slap together a portal system based on someone else's implementation. If you are building something from scratch for a customer, then you have to gather your customer's requiremnets. If you are building a generic portal system for a university, then you need to do some research and take a sample of the education sector and find out what are the things that are usually included in an educational type portal for students..
What comes to mind for me is that you need to authenticate your users for one. They will probably want to interact with each other so you need some type of messaging/communication component. They will interact with teachers, there will be class information, schedules, coursework, profile information to includes classes taken, finicials, etc, etc, etc....