Hi Gosia,
Try Photopills guide. The app is the best for astro photography. Although I was not able to fully use it, because it’s too complicated.
https://www.photopills.com/articles/milky-way-photography-guide#step4
The picture you referred to was taken at Cambridge, MD (Eastern Maryland on Rt-50), another good location is Assateague Island, close to Ocean City, and of course Skyline Drive on Shenandoah national park. I used my 24-105mm f4.0 lens (24mm, at f4.0), ISO 4200, probably 20sec. I recently bought 20mm prime f1.8 for Milkyway this season. Plan to go out in a few wks.