In the Season Menu you can find the current PvP Season's progressive rewards.

The PvP Season Points (4/5 in the screenshot above) can be collected from various activities. Tapping on the information button to the top right of the screen will display all the places where you can earn them and also show how many you get through each action.

In order to gain access to the rewards on the left of the screen, the Season Pass needs to purchased. It can be purchased by pressing on the "Activate" button on the initial screen. Once it's purchased, the rewards to the left of the screen are unlocked, up to the point you progressed so far.