Touge (峠 tōge?) is a Japanese word literally meaning "pass." It refers to a mountain pass or any of the narrow, winding roads that can be found in and around the mountains of Japan and other geographically similar areas.
add an alpha channel (transparent one) on the layer you want to erase parts of, if you can't add one the layer will already go transparent when you erase that particular layer.
edit: Screen recorder is messing up, i'll try making a pic instead. But before i do i'll write out the instructions.
USE 1: Simple Erasing.
1. Open a picture of your choice.
2. Go to Dialouges -> Layers , to open the Layer window.
3. Then go to Layers-> New Layer
4. Name the layer to whatever you want, then select fill layer with "transparency" (This creates an alpha channel)
5. Put something new on the layer (Paint something, paste something etc)
6. Select the eraser tool and erase what you don't need.
7. The image on the bottom layer should show through where you have erased parts of the top layer.
USE 2: Image onto Image.
1. Open your background image.
2. Open the second image in a new window.
3. On the background image create a new layer, filled with transparency.
4. Copy and paste the second image onto this new layer.
5. Erase unwanted parts of the second layer so the background shows through.
6. Use zoom and different brushes to accurately crop the part of the image you need to remain visable.
7. Move, rotate and scale the second image until you have it where you want it.
USE 3: Erasing parts of a Background. Method 1
1. Open your background image.
2. Go to Layer-> Transparency -> Add Alpha Channel
3. Erase unwanted parts of the background.
USE 3: Erasing parts of a Background. Method 2
1. Open your background image.
2. Select the "Lasso" tool.
3. In the brush options select "Feather Edges". Set the radius to around 20.00
4. select the rough area you want.
5. Cut and paste your selection into a blank image
6. The pasted image should fade into the background, from where ever you selected it.