Sure, it's annoying to have to wait for overseas shipping. I get derailed on a project (or solve it another way) by the time it shows up.
Here's the schematic for the relay. It uses a little 2N7002 MOSFET (transistor) to drive the relay. With the caveat that I provide no warranty and dealing with 120v/240v is dangerous, it should work just fine. Here's how to hook it up:
I'd suggest testing with no load or a LED+resistor instead of high voltage. You'll be able to hear the relay clicking if you have it working correctly.
So, on to the Pi. Assuming you have the GPIO stuff set up, the following commands will put pin 11 into output mode, then turn it on and back off.
gpio -1 mode 11 output; gpio -1 write 11 1; sleep 1; gpio -1 write 11 0; sleep 1
You can rerun that as many times as you need until you have it working- especially handy if we guessed wrong on the D1 pin on the Wemos board. Yes, it's okay to keep setting 'output mode'. Doesn't hurt anything.
Let me know. Again, be careful with the high voltage!