network for tic tac toe game

i build the tic tac toe game supported by unity and i want to extend it by making it a multiplayer game using socket io but i don't know where to start

 

That's not an easy task at all. Making a game with online multiplayer is extremely difficult compared to making an offline game.

You can start by learning about game networking in general.

You can learn about networking in Unity here:
https://unity3d.com/learn/tutorials/s/multiplayer-networking

To use socket io you will need a plugin like this:
https://github.com/NetEase/UnitySocketIO

 

I agree that a networking game is better attempted when you have some good experience in coding.

When/ if you want to try, I believe that Unity's HLAPI (high level API) for networking could assist you. There are many introduction manuals and tutorials that you could use.
Luckily, you have a fairly reasonable goal in mind for your first multiplayer. Tic tac toe is very simple, so I would say it's not that scarey, provided you are comfortable with coding to some degree.

I'm not super familiar with Unity's networking HLAPI but I have read about it a number of times, and I believe getting that game working with it wouldn't be too hard.

Good luck

 

Having extensively used both the Unity HLAPI and Photon Unity Networking (PUN), I can say that PUN will almost certainly be easier to get on with.

The current state of the HLAPI and its lack of support/development make it frustrating and overly difficult to work with.