I could not find a place on the Lian Li web pages to download a manual for these fans. BUT it does say clearly that the 3-pack includes their Controller, AND that you MAY connect that controller to a mobo 3-pin ARGB header if you have one, but whether you actually USE the mobo signals to control your lights is an option you CHOOSE using their software tool.
The way these Controllers work is commonly that they have a connection to a SATA power output from the PSU for power, a cable to connect to a mobo case fan header using the new PWM Mode to get that signal for fan speed control, another cable to connect to the mobo's 3-pin ARGB header IF you have one, a third cable to connect to a mobo USB2 header, and output ports for the fans. You download and run their software utility, L-Connect. This uses that USB2 connection to communicate with the Controller, and that is how you do all your control adjustments. ONE of the options in that software is to allow control of the lights to be done entirely by the ARGB signal input from the mobo header. BUT if there is no such signal, you simply cannot make that choice, and all control is done with L-Connect. You do NOT need the mobo ARGB header, nor do you need any additional control nodule.
An alert. I see by the web page that Lian Li has had trouble with the L-Connect software, and recommends two things currently. One is to download and install a firmware upgrade to the Controller, and the other is some procedures to update the L-Connect software so it all will work as planned. Before buying, check with Lian Li whether they really HAVE fixed their problems so that the system works!