There's two ways you can control with this UP controller, it has an HI and LO setting.
The way it tells you to set it up for a freshwater tank is to use the HI setting which is the traditional method of closing the solenoid when the pH drops to a trigger point that you set, it will trigger the closing of the solenoid when the pH drops 0.05 points past your set point (as long as the solenoid power is plugged into the controller power block).
Alternatively you can use the LO setting which is intended for Saltwater use for dosing Kalkwasser, the way it operates here is that it switches on the the power when pH drops 0.05 pH past your set point and will turn off the power once it climbs 0.05pH past the set point. Instead of powering the solenoid you use either a power head or an Airpump to increase surface agitation within the tank, this increases the aperture of gas/air contact within the tank and allows the co2 to gas off.
The difference between the two methods is that the first method using the HI having solenoid control will mean all the lines will depressurise when gas switches off and there is a lag in it pressurising again when it comes back on, this means that the pH may climb beyond the 0.1pH variance (0.05 either side of set point), a variance above 0.1 is fluctuating co2 and invitation for BBA. The second method using the LO setting means the gas never switches off, the lines never depressurise so no lag and the variance remains within 0.1pH as long as the method used to increase gas transfer aperture is efficient enough. The variance of 0.1 has been said to be an acceptable fluctuation for plants not to suffer a shortfall. You can use the LO and adjust the level you off gas so that it hovers at your set point.
I'm currently using the LO setting.
You don't have to use it as a controller you can use it just to monitor the pH drop so you can correlate with a drop checker. You don't need to know what the exact pH off the tank as there are a few things that will influence the accuracy of the probe, the first is that if the TDS of the water is low the probe will have a hard time reading the pH, it will read but it will take a few minutes to stabilise and may be inaccurate by up to +/- 0.5 pH points. The other thing it is influenced by is impeller noise from a canister filter (stray voltage generated by a rotating magnetic field), you can test this by taking a reading with the pumps off, when you get a stable reading you turn the pumps on, if the value drifts it's being affected by stray voltage (voltage not current, current in a tank is a very very bad thing to have). I recently re calibrated my probe to tak into account this effect (set the pH to what the reading was before pumps on). What is important here is that it doesn't really matter what the pH exactly is you just need to see that the pH drops by an amount that correlates to a drop checker colour indication you desire (drop checker will lag by a couple of hours). My drop checker is always blue at lights on but my pH has dropped to a point where the DC will eventually go green/yellow some time later. This is my daily target pH but the tank pH may drift between water changes so I need to always check the drop checker to make sure I get it the colour I want at the start of each week, it's a very small drift but it's enough to cause a lot of confusion and a little bit of BBA.
Controller is just another tool, it's not foolproof but it can help you understand just how much co2 you actually need to inject to get the desired pH drop to keep your plants happy under their available lighting. You want to get the injection balanced enough for the controller never to be triggered, it's nice to know there is a back up safety net just in case something bad happens like an EOTD, I'd rather have grumpy plants and a bit of BBA than dead fish!
Since you already have it its worth trying it out just to see if you can get the 1 point pH drop and have it correlate with a green drop checker, it will at least tell you if you are going in the right direction.
Sorry that was a bit long winded, any questions feel free to ask!