Where do I put PlayerPrefs.SetInt?

I’ve been creating an upgrade menu and in the menu I have multiple buttons. When you click a button it will bring up a menu on the bottom showing your stats. However, despite setting the Speed Level(“Speedlvl”) to 1 it continues to display it as 0. I’ve tried changing it to 5 or any other number but it doesn’t work. I can’t put it in the start method either because I want to save the player’s speed level. Thanks for the help guys, here’s the script
(Also not sure if PlayerPrefs is the best way to save things but it’s the only way I’ve heard of)

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class UpgradeText : MonoBehaviour
    public Text Title;
    public Text Balance;
    public Text Description;
    public Text ButtonPrice;

    public Button Purchase;

    public int Price;

    public int Speedlvl;

    public void Level()
        PlayerPrefs.SetInt("Speedlvl", 1);
    public void OnSpeedPress()
        Title.text = "Speed - Level " + PlayerPrefs.GetInt("Speedlvl");
        Description.text = "This upgrade increases the player's movement speed";
        Balance.text = "Balance: $" + PlayerPrefs.GetInt("Bal", 0);
        Price = PlayerPrefs.GetInt("Speedlvl") * 10;
        ButtonPrice.text = "Upgrade for $" + Price;

It doesn’t look like you are ever calling Level()

you have to actually call Level(); somewhere in order for the action to take place.