I completely agree, I can't even get it to work lol.
Quick guide for you.
1. find a rough tear/blood of the mountain while mining.
2. DO NOT cut it in a jewlers, keep it as a rough stone.
3. Using the furnaces menu, find the water/magma wells. Tears for water, Blood for magma
4. Place the 3x3 well somewhere, points to note on placement, the water/magma is generated on the Z level below the workshop at one of the core directions, as such you need a channel or hole of anykind at these points (M) to function, See below for an example.
W = Workshop
M = Magma
M
WWW
MWWWM
WWW
M
The Z level below will look like this.
M
M M
M
5. When using the well you are given a choice of options, one is the direction of flow NSEW, second is the flow rate 0-4. The final option is to turn off all flows. From my own experience the option to turn off all flows DOES NOT work and results is only fun. So if you for example start a new magma flow North at a rate of 1, then wish to stop it later. Go back into the well and set a new flow North at a rate of 0.
That is mostly it for wells, once you get one working and see them they are fairly straight forward.