How to use Sparkfun Beefcake relay from Raspberry Pi

My confusion is that I thought this kit was designed for an Arduino type? And aren’t the IO pins higher voltage than the Raspberry Pi? (5V vs 3.3) ?

Thanks

PS happy to dig out the other discussions - they are mostly about other mains relay boards, not the beefcake

Here’s one, from the raspberry pi.org where they were using a level shifter:
https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=106022&p=731710

and here’s one from your forum:

http://forums.pimoroni.com/t/controlling-sparkfun-beefcake-relay-with-explorer-hat-pro/2886

More later…