Having Trouble With Masking in Photoshop (22.3)

[BettichRoss]

Hello! I am pretty new to Photoshop (22.3), and I was using the masks very well the other day, but today I got on to Photoshop, and my black/white Brush tool didn't work as an eraser?! The thing is... It was working perfectly the day before, and I haven't changed any settings! I even tried resetting tools to default! I'm guessing that I am doing something severely wrong. So I will post a video with this. Thank you!

[marliton]

Hi. Please select the black color using the Foreground color in the tools panel.