should just take a feed off the coil pack... it wotn be hard, and should tell you in the insstructions, think they may of scammed you with the sender?!? it litterally takes a signal each time the coil fires.
probably has a switch for cylinders aswell, ie 4,6,8, if it has then obviously set it to 4.
other than that its a case of +ve feed for the light(if it has one) that can be tapped in somewhere handy on the dash,+ve feed when the ignition is on, and earth it.