Using Tractor beams

[Deantwo]

That empty Wiki page was the first place I looked.

It isn't empty. You just have to expand the "Related patch notes" box.
In case you can't find it yourself:

Update 2016-09-15: Tractor Beam
Tractor Beam
Tractor beam bay module now works. Here are the details.

• Target must be a spacecraft. Nothing else can be towed with a tractor beam.
  
• Target must not be moored.
  
• Target must have shields down. If any shield side is down to 2 or less energy, the target can be grabbed with a tractor beam. (Same test for blocked transporter.) Raising shields on target disconnects the tractor beam.
  
• Tractor beam is operated at fire control console. Select a target. Attach and detach the tractor beam by pressing the yellow T button.
  
• Tractor beam has a range at which it can attach to targets. Once attached, the target is held at a safe distance from the towing vessel. It can be pulled or pushed with the beam, so I suppose it is both a presser and an attractor beam, a.k.a. tractor. It seemed wrong to separate the two.
  
• Tractor beam uses a burst of power to fire, to attach to the target. A light blue bar under the capacitor level bar shows amount of capacitor consumed when fired.
  
• Tractor beam always fires at maximum power setting.
  
• Tractor beam consumes power steadily while on, roughly equivalent to running the same number of gravity drive units as tractor bay units.
  
• Target's maneuver acceleration is reduced by the amount of acceleration that would be achieved by attaching maneuver drive units to the target, equal to the number of tractor bay units, at the tech level of the tractor beam. The resulting acceleration is affected by the mass of the target. Design analysis shows this value for a target of your equal mass. If tractor power exceeds maneuver acceleration of the target, they can barely move. This has not been tested.
  
• Target can be towed through a wormhole. Target does not have to have a wormhole drive.
  
• Target can be towed at light speed or warp speed to deadhead to other systems.
  
• AI no longer shoots tractor beam at enemy as if it were a weapon.
  
• The ability to scrap ships for parts and technology is on my short list. I didn't have time to do it in this update.
  

Most likely you didn't lower the shields on the station.