its actually rather simple. all you need to do have a basic translucent material is to change the blend mode to translucent (see picture below). just select the material node in the graph and you will be able to modify its properties in the details panel. then connect a image or script to the opacity pin, in this case i used the alpha channel from a texture. the opacity is a 0-1 or black-white value where black is translucent and white is opaque. there is also another blend mode called masked which will also make sections of the material fully translucent but it uses the opacity mask pin instead.
