Unsure of correct steps with Arduino Uno + USB

So I have an existing project that has an LED strip and when I press a button, it animates a bar of color down the strip. I am trying to make it so when I press a button on Blynk, it will do the same thing. But I must be missing some steps in the tutorial because nothing works.

My Uno is on COM3 in the IDE. I am using the FastLED library.

So - here are my issues:

First - I assume I can’t upload code and also have the batch file that maps the port running, right? So what is the correct order? Do I upload the code, then run the batch file, and then do a reset?

Next - when I run the batch script I get this output:

Connecting device at COM3 to blynk-cloud.com:8442...
OpenC0C("\\.\COM3", baud=9600, data=8, parity=no, stop=1) - OK
Connect("blynk-cloud.com", "8442") - OK

Is that correct? Incorrect? I have no idea…

Next - DebugSerial - what ports should i use?

Finally- when I add the standard lines from the sample to my existing program, it stops working. To be exact, adding this line to setup:
Blynk.begin(Serial, auth);

is enough to make my program no longer work. Here is the entire function:

void setup() {
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
  memset(leds, 0, NUM_LEDS * 3);
//Blynk.begin(Serial, auth);

If I uncomment that line, the app does not function, it just hangs. Is there some compatibility issue with FastLED?

Any help would be greatly appreciated.

Since UNO has only one hardware serial port, you must:

A) Remove/comment out any debug and/or serial writes as they will cause issues… or switch them to a 2nd software serial port and use a TTL-USB adapter for that function (you must also use a separate terminal program like Termite)

B) Load sketch

C) Run USB-Connection script to connect your UNO, via primary USB, port thru your PC to the internet and the thus the Cloud Server. Script must stay running to stay connected.