Yeah, a pump isn't just a single task sort of addition to your setup.
That was taken many years ago. My stand was always in a constant state of evolution. Back then there weren't as many sources as there are now, so I just kept adjusting things as I went to make it work for me. The pump is behind the carboy. I set it up with 2 inputs & 2 outputs, just to make it easier to do that entire list of things previously mentioned. In this particular picture I'm running an immersion chiller, with the output going into the HLT to be used as cleaning water. The pump is recircing to/from the BK to make the chiller more efficient.
The 2 inputs are on the left side of the pump (carboy). One from the BK, one from the MLT. The 2 outputs go to the HERMS coil, which is built into the HLT (where you see the 2 hoses), and to the BK. The thermometer on the HLT is the output of the HLT itself, which can be hooked to the top of the MLT & gravity fed for sparging. The flow rate is controlled by a ball valve on the output. All other flow rates are controlled by the 2 independent outputs on the pump itself.
So when I start to brew I heat up my strike water in the MLT by an electronically controlled HERMS (using the pump to circulate). I kill it for a moment to dough in & then start the pump back up to maintain temp... and at the end to ramp/mash out. When it's time to sparge, the pump output gets changed so instead of the wort recircing back to the MLT, it gets sent over to the BK. The water from the HLT is then gravity fed to fly sparge while the wort is being pumped over. Once the boil is almost done, I start the pump again, pumping from the BK back into itself. It helps prevent scorching & sanitizes the pump/hoses that I'm going to use while cooling. Flame out, I use the pump on that same loop, as previously mentioned, to make the chiller more effective... essentially a whirlpool. Once I hit temp, the output then changes to the fermenter.
I do things a little differently these days - bigger system, CFC, auto-sparge, RIMS, etc., but the process is essentially the same.