you may be further ahead of this than i.
having recently purchased a kk quad and fs-i6,
bind the two together. ought to be easy, instructions for both easy to find.
*connect the vehicle to betaflight*
in betaflight, observe the receiver page
turn your fs-i6 on, and activate the switches and sticks to confirm the vehicle is receiving.
i forget the name of the betaflight page that has options on it for activating stuff, "modes" is it?? but on my quad it lists various flight modes and onboard accoutrement, eg. buzzer et al.
these fields are big horizontal strips across the page, and it allows you to assing a controller (eg. aux1 et c.) to them.
here's the fun part: on my quad, the "arm" function is activated when the switch is high. i think the range was like 1100 to 1700. *but* for some reason the switches on my fs-i6 threw 1996 when high, which i guess is unusual.
as you may parse, 1996 is higher than 1700 and thus outside of th eactivating range. so, i could flick the switches all day and get no response.
you need to connect it to betaflight so you can see what it's doing