First time using the Raise

But where are the missing keys? I need my F keys and arrows!

Every Raise has a preinstalled layer 2 with all the other keys present on larger keyboards: the arrows, the F keys, the number pad, and the media keys... you name it.

But how do I access that layer? Do I need an interdimensional portal?

Not really; you just need to hold the appropriate key.
By default, you can access layer 2 by holding either of the two inner thumbkeys in the bottom row of the thumb cluster (see image).