How should I make a Stair Hit Combo System?

Hi, I'm remaking a popular game I made similar to Broken Bones. I want to add a combo like system like Skate 3 for example, but I'm not sure how. This is what I got so far:

local player = game.Players.LocalPlayer
hitNumber = 0
wait(0.25)
local leaderstats = player:FindFirstChild('leaderstats')

leaderstats:FindFirstChild('Hits').Changed:Connect(function()
    if player.Character:FindFirstChild('hum') then
        hitNumber = hitNumber + 1
        script.Parent.TextTransparency = 0
        script.Parent.TextStrokeTransparency = 0
        script.Parent.Text = 'HIT COMBO: '..hitNumber
    end
end)

When the player hits the stairs, they earn hits, which is why I did this. Probably badly made, so some help would be great. Thanks everyone. :)