How to get past black barriers in hollowknight

The ability's name is Shade Cloak, but it's a late game ability that you won't be able to get until you figure out how to open the door at the bottom of the Ancient Basin.

As with all of the mechanics of Hollow Knight, it's telling you to leave and come back at a later time. That particular dark wall can be bypassed later with an upgraded version of the dash. I suggest if you want to play the game blind that you look for it or come back to it later, and if you really can't find it then look it up at that point. Enjoy Hallownest!