You should have two photocells and two transmitters per bollard. Transmitter is just for signal and it is battery driven, you should only install batteries inside and close cap.
In the instructions there are wires but it is not necessary in your case.
You can find the image of installation process of photocells and transmitters at the following link:
Photocell should be aligned with transmitter and connections are next:
You can find the image of alignment of the photocells and transmitters and connections at the following link:
Power for photocell is connected from marked positions on photocell to V+ and COM on control board of Bollard. This is same for all photocells.
You can find the image of connection between power of the photocell and control board of the Bollard at the following link:
Signal connections goes from photo to LE and COM for one photocell of Bollard and LA and COM for other photocell of Bollard. It doesn't matter which one you connect first.
You can find the image of wiring diagram between two photocells at the following link:
COM connections are same so you can pick which one is more suitable for you.