Custom SAMD21E18A board


i have a personal board build with an samd21e18a, I would like to create the board in Platformio, I found this example for a samd21e17a here, I have already my variant files etc for my board.

But I have some question, first do you think I can start with this template for my samd21e18a? In my case I used a bootloader but in samd21e17a example No ldscript are specify,

"arduino": {
       "ldscript": "flash_without_bootloader.ld"

Should I put mine here? Because in my previous configuration for Arduino Ide, I have these lines :

And this line replace extra_flags example? {build.usb_flags}

What do you think? Or maybe somewhere samd21e18a template exist?