What exactly is meant by 1 additional hit die?

Question

The dnd5e starter set explains that when you levelup you are rolling for your additional hp you gain. But for the sheets is stated, that you get 1 additional die with each level.

Now for me the following isn't clear: Does this mean with each levelup I roll an additional die? Like for lvling up to 2 rolling 1d8 to determine the increase and leveling to level 3 rolling 2d8 to determine the next increase?

Or is this just another wording for "Don't forget that with each level your HP increase!"

Answer 1

They are two separate things. Let's say you are a Rogue (1d8). When you level up, you roll 1d8 to determine your HP increment, no matter what your level is. Also, you have a reserve of dice (d8). When you perform a short rest, you can roll one or more of those dice in order to recover HP. The higher your level, the larger your dice reserve (at each levelup, you get 1 additional die for this reserve).