Arduino + Blynk

Hello friends,
I am totally lay in programming, and the people at Blynk are not very receptive to doubts ..
I need help with a project with Blynk, I will use a sensor (stitch) as input, and when triggering an output (relay) start counting a time and store it on the blynk virtual lcd and when you release the sensor, the counter stops but the time is stored, and when you turn it on again it continues to count the time and so on.
If possible a virtual button to clean the lcd

Tanks

Do you have a question?

I would like to know if anyone has ever needed any code like that, because I don't even know where to start, I don't understand anything about programming

not exactly, but this seems similar

How to sum current duration in next duration

not sure what you expect. this forum is for helping people with there coding errors, not teach them to program

Tks