KC868-server Ultrasonic and Gas sensors

[Mandlap]

Please advice on testing ultrasonic sensor (HC-SR04) with KC868-Server. I have a power source of 5Vdc. I'm trying to figure where to connect the "Echo" and "Trigger" pins on the Server and will appreciate the ESPhome code. 
I'm also testing the gas sensor (MQ8), trying to figure where to connect the "Dout" and Aout" pins on the Server and will appreciate the ESPhome code.

[admin]

what's your ultrasonic sensor output signal?
what's your gas sensor output signal?

[Mandlap]

what's your ultrasonic sensor output signal?

what's your gas sensor output signal? 

what's your ultrasonic sensor output signal? Electric frequency signal, high level 5v, low level 0v.  Detection distance: 2cm~450cm. Trigger Pulse Input. Echo Pulse Output

what's your gas sensor output signal? Has a DO switch signal (TTL) output and AO analog signal output. DO output: TTL digital 0 and 1 (0.1 and 5V). AO output :0.1-0 .3 V (relatively clean), the highest concentration of voltage around 4V. The analog output voltage, the higher the concentration the higher the voltage. For gas, natural gas has better detection sensitivity.

[admin]

if you want connect to ESP32 pins, they are using 3.3v level, so you need have a convert circuit.
then you can connect with IO1--IO4 (beside ESP32 USB-C port on PCB)

[Mandlap]

if you want connect to ESP32 pins, they are using 3.3v level, so you need have a
then you can connect with IO1--IO4 (beside ESP32 USB-C port on PCB)

if you want connect to ESP32 pins, they are using 3.3v level, so you need have a  convert circuit.  - I do have a DC/DC stepdown convertor (3.3v not a problem)
then you can connect with IO1--IO4 (beside ESP32 USB-C port on PCB)   - the connection with IO1-IO4 is this a separate ESP32 module? or KC868-Server?

[admin]

IO1-IO4 is control by ESP32 module:
IO-1: GPIO4
IO-2: GPIO5
IO-3: GPIO18
IO-4: GPIO19