Which part of the plugin do you need help with?
Use the Title inspector to switch from a shutter to a flash effect.
Applied Shutter Effect
Here’s the VShutter-Flash title effect connected to a clip after the Viewfinder effect focuses in the video. Note how the VShutter-Flash effect is placed underneath the Viewfinder effect. Note also the Hold frame that starts after the shutter closes. To create a hold frame move the playhead to the frame you want and press Shift-H.