Not at all, Barbara.
If you want to - and have the patience of a saint - you can just pick up and drop each yarn as you need it. No-one could knit something bigger than a coaster this way though I'm convinced!
At the opposite end of the spectrum, you can hold both yarns in your left hand, the best video of which is this from DROPS (they claim they didn't know what language to record it in if not Norwegian .. err ... ). Anyway, don't worry about that for now!
I should say, btw, fairisle is inherently harder to do in purl than in knit, which is why even for flat things, extreme knitters will do them in the round and then cut them at the end 
. This barbaric practice is known as steeking but let's not talk about that either!
Liat shows the main methods in her , including both yarns in the right hand. However, to do it two-handed you don't have to be able to knit continental. You can more or less drape the left-hand colour over your index finger and pick it up when needed, just tension it a bit as you do it. What you should do in this case (and indeed with all methods) is make sure you identify, row-by-row, which colour is dominant and which colour is subordinate. In Liat's video the green dominates. So you knit along merrily in green, then grab a blue off your left index finger, then carry on. This also means the green will float 'above' the blue behind the work without you having to think about making sure you pick up the blue from below the green to keep the back looking very even like in the stranding example on this page.
Obviously this dominant colour malarkey is not vital for getting started! But it all helps.
It's definitely worth practising and doesn't take long to get right, especially with the incentive of not having to pick up and drop the yarns every other bloody stitch! If you would like an idea of a test piece that's a bit quicker than a snawheid hat, these are two Milo tank tops I did with the Snawheid pattern on them.