Due to the extensive use of breakout boards, constructing this circuit is mostly a matter of wiring the boards together.
Because of the power requirement of the WiFi transmitter, a 5v supply of at least 1A is advised. It connects to the USB pin of the Feather, Vin of the BMP280 and AirLift, and Vcc of the Air Quality Sensor. The grounds of all boards connect together and to the power supply's ground.
This connects to the Feather's I2C interface as described in the BMP280 guide.
This projects uses the Ultimate GPS Featherwing so, while the connections are shown above using wires, it simply plugs onto the Feather, using TX and RX.
This also requires a serial interface, but thankfully the SAMD51 has plenty of those. We can use A2 and A3 as TX and RX, respectively. The Sensor connects via the supplied cable and breakout. In the wiring diagram above it's shows as the header that the breakout can plug into. See the product guide for more information.
The AirLift breakout connects to the Feather's SPI lines as well as D6, D9, and D10 for RST, BUSY, and CS respectively.