In ExpressPCB Plus if you want to remove inner layers to add traces or your own copper plans you want to select the inner layer you want to work on in the box at the top labeled Shape. Then select the rectangle tool, then right above Shape at the top select the Drop Down and select Keep Out Fill. Then draw your keep out to remove all or part of the inner layer. Then you can add your own traces and copper pours. You will need to use the default pour if you want to have component and pads and vias attached to the pour. You can use the Outline tool to make the shape you that works best for your design.
Keep in mind there is a tool under the View tab at the top that says Show Pours. This should not be changed from All unless you want to do an alternative view for viewing just what you have added. The Elements option will hide the default copper layer but will not remove it. Only the All option shows exactly what your board is.
In ExpressPCB Plus if you want to remove inner layers to add traces or your own copper plans you want to select the inner layer you want to work on in the box at the top labeled Shape. Then select the rectangle tool, then right above Shape at the top select the Drop Down and select Keep Out Fill. Then draw your keep out to remove all or part of the inner layer. Then you can add your own traces and copper pours. You will need to use the default pour if you want to have component and pads and vias attached to the pour. You can use the Outline tool to make the shape you that works best for your design.
Keep in mind there is a tool under the View tab at the top that says Show Pours. This should not be changed from All unless you want to do an alternative view for viewing just what you have added. The Elements option will hide the default copper layer but will not remove it. Only the All option shows exactly what your board is.