Vortex Sound Research

Hi, I’m a complete novice to synths. I’ve actually never really played one before. It’s always been an appeal so I’ve finally decided to bit the bullet and buy some gear:

Arturia Key steps Behringer D Volca Steps Scarlet 2i2

I want to hook this up to my iMac.

I know this is a stupid question but I don’t seem to be able to find any noob videos on setup. Wondering if you guys can help me know what cables I need to buy for the best way of setting this up. Also, any rec on mid priced speakers would be amazing.

Thanks a bunch!