New user, need help to use Fn esc on startup.

I gave up on my ergonomic split wireless keyboard and bought a MacAlly Mac specific wired split keyboard, BUT, the short-sighted designers decided that they will not follow Mac operations and require that every time you startup the computer, you have to use Fn esc to use standard F keys. This is the only wired Mac split keyboard I could find, so in researching how to automate that, I found out on the Keyboard Maestro forum that BetterTouchTool can use the Fn key. I downloaded BetterTouchTool and couldn't figure out how to get the Fn esc to activate on startup. Any help will be greatly appreciated.