Easy Transfer is NOT a Blynk process, and I am not going to sit down and make a tutorial… however here is a few pointers… the rest is up to you to experiment with.
Instead of feeding the data “live” you should be applying some logic code that checks the “live” data from the button or whatever, so that it only sends the data via ET when/if it changes state from last time checked
With ET you have to setup the shared variable in the structure first… did you do that?
I would also avoid directly sending the “live” data as it may not translate properly… remember, the sensor is probably putting out a float while ET is using some form of serial conversion. Perhaps transfer the sensor input to a variable, process it for change checks as needed, then use that variable for the ET transfer.
And again, only send the data if it has changed, or only send it on a timed schedule (probably timed is best for Temp and Humidity anyhow).