Thinking back to his Divination classes (which he'd always abhorred and rarely paid much attention in), he remembered there being a tea kettle and a teapot involved in this process, so he felt rather impressed with himself for knowing what a tea kettle was.
However, that high didn't last long because they were not using magical fire or the fire from a fireplace to heat the kettle. No, they were using that big, muggle square thing with knobs all over it.
Regulus didn't like it.
And he frowned while Ned was trying to explain how the thing worked, only catching half of what the man said.
In his gut, he fought a battle over wanting to run out of the room, to resist learning how to use the muggle contraption versus the need to eat, to just know how to make basic food to survive.
Regulus had no other option, so the need to learn how to cook food on muggle inventions won the day. This went against everything he was raised to believe, but now it was a matter of survival. He had to reassess his values. At least enough to eat.
He shot Ned a look when the man told him to clean up, but after a second's pause to consider what retort he could use in protest, he reasoned that this man was showing him how to make tea, maybe he should put the biscuits away for him.
Compliance didn't exactly mean Regulus did it correctly. It took him a few tries before he got the boxes of biscuits stacked well enough so the cupboard would close. Even then, it was a precarious situation.
"Why isn't any of this run on magic and not your- your-" he couldn't remember what Ned had called the stove, so he stumbled over the words until he came up with a name of his own, "big gas flame box? Where's the fireplace?"