how does the tilt of the the earths axis and its movement around the sun play a part in the changing of the seasons in the northern hemisphere?

Because it makes earth able to receive sunlights in different directions.

Explanation:

Most of it, seasons exist because of the different impact directions of the sunlights, and this differences are there because of the tilt of earth axis.

Also, the rotation around the Sun give us the heat and cold seasons, during winter season, earth is further away of the sun and summer-hot seasons happen when earth is closer.

But, seasons only are presence in north and south hemisphere, not in the center. This happens because of the inclination of the Earth axis, this makes sunlights hit in the same direction (approximately) in the equator, no matter the season, but this doesn't happen in hemispheres.

It is summer in June in the Northern Hemisphere because the sun's rays hit that part of Earth more directly than at any other time of the year. It is winter in December in the Northern Hemisphere, because that is when it is the South Pole's turn to be tilted toward the sun.