Hi Raul
With the wemos D1 , little expensive but good ESP8266 choise, have you received the ultrasonic module and the relay module? You can try to connect it to your Wemos d1 following the schematics that i previously have given to you. Pay attention to the voltage : Esp 8266 GPIO are 3.3v while most of the boards are 5v. You can use the 5v out of the Wemos board for the v+ connection but you have to convert voltage on Esp Gpio input lines; the few components in the schematics are for that function.
For the relay (normally 5v) with the appropriate driver transistor may be directly connected, pay also attention that relay contact are rated to the pump current and voltage.
I will try to answer ASAP your post but I am afraid we are in 12h time difference.
Paolo