Using STEMMA QT cables, plugging everything together is easy. And with the available bolt kit, there are various ways in which the boards can be fastened together, or not, depending on how you want to arrange things.
Using STEMMA QT cables, the basic wiring is very simple - just plug everything together. There are several different STEMMA QT cable lengths to choose from. Also, the ordering of the sensors should not matter.
If you want to stack things together, the M2.5 hardware kit can be used. In order to stack more than two things together, you'll need more than one bolt kit. The SCD40 should end up on top to give it enough clearance.
Using two bolt kits, it's possible to stack all the boards together. However, this may be too chonky. The STEMMA QT cable may also interfere with plugging into USB port as well.
Using one bolt kit, just the BME280 and SCD40 can be stacked together. This allows the sensor package to be tethered separately from the Trinkey QT2040.