The steps for selecting the arc layer in ps vanishing point are as follows:

1. First open the file that requires perspective painting, select "View" in the menu bar and select " Display the "(Show)" command and select "Grid" and "Guides" in the drop-down menu to better assist drawing.

2. Select the "PathSelection Tool" in the toolbar, and then create a shape that requires perspective (such as a cube) in the direction of the vanishing point.

3. Create a new layer and use a brush or other tools to draw or operate the required arc on this layer.

4. Go to the "Windows" tab and select the "Layers" command to open the layers panel.

5. Click the "MergeDown" button above the new layer to merge the new layer with the layer that needs perspective painting.