How do i make a Fps game on unity 5

All what I can suggest is to start with a simple singleplayer FPS, not a multiplayer. Make a base singleplayer. on youtube are a lot of vids. After that you should start learning Photon or uNet to make a multiplayer Here some vids

https://www.youtube.com/watch?v=UK57qdq_lak&list=PLPV2KyIb3jR5PhGqsO7G4PsbEC_Al-kPZ
https://www.youtube.com/watch?v=f8tAI0ITV6s&list=PLZcQtrQ9JcLye36JLtP7GlV6hC_syi4f1
https://www.youtube.com/watch?v=0fGB2H1AGP8&list=PLZ1b66Z1KFKh-auyvzNkOBFLWf6dH6iEH

Here is a code that i made that made coding more easier

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Wepon : MonoBehaviour {
 
     public float range = 100f;
     public int bulletsPerMag = 30;
     public int bulletsLeft = 200;
 
     public int currentBullets;
 
     public Transform shootPoint;
 
     public float fireRate = 0.1f;
 
     float fireTimer;
 
     // Use this for initialization
     void Start () {
 
         currentBullets = bulletsPerMag;
     }
     
     // Update is called once per frame
     void Update () {
     
         if (Input.GetButton("Fire1")) 
         {
             Fire ();    
         }
 
         if (fireTimer < fireRate)
             fireTimer += Time.deltaTime;
     }
 
     private void Fire()
     {
         if (fireTimer < fireRate) return;
 
         RaycastHit hit;
 
         if (Physics.Raycast (shootPoint.position, shootPoint.transform.forward, out hit, range)) 
         {
             Debug.Log(hit.transform.name + " found!");
         }
             
         currentBullets--;
         fireTimer = 0.0f;
     }
 }
     

That is just v1