We actually have to be more specific about this lemons variable. Remember, we made it in a different script, and Roblox needs help looking for it in that other script.
The lemon is hiding in the leaderstats, which are hiding in the player.
You're going to set the "player" variable to long line of code. This line of code is asking Roblox to grab a player object from the character variable.
(Character is the parent of the "other" thing that ran into your lemon.)