my guess is once the remaining " + " all bundled up ( except turn signal "+"), the running light will be on once bike is on and when brake is applied, the light will be brighter?

led turn signals will require a resistor for each side or an electronic flasher

I didn't watch long enough to see if he showed you how he made them work - but you need something like this:  (It is somewhat simple to hook up if you can read and follow directions and follow a wiring diagram - but it is not plug and play and there are quite a few wires to hook up correctly).

https://www.ebay.com/itm/Badlands-ILL-01-Run-Brake-Turn-Signal-Module-All-Har...

And....I have a few comments.

You only need to have single filament turn turn signals for this controller - so you would wire in the red light on the aftermarket turn signals you bought, and not use the white wire.

The stock tail/brake light is likely much brighter than your aftermarket turn signals......and/or much more visible in daylight.  I have ridden behind bikes on Poker Runs or just daily riding, and the cheaper aftermarket turn signals that are not DOT approved are hard to see in direct sunlight - they just aren't going to put out enough light to help keep you from getting run over by a distracted driver.  A lot of custom bikes have tail lights, brake lights and headlights that are pretty much useless on a bike that is going to be ridden on public highways.

If you are going to eliminate the rear running/brake light - at least use lights that are DOT approved.....or at a minimum that are very bright.  The Harley Davidson Roadster uses a pair of rear lights.....and I am sure they are DOT approved.