[i.h]

No you don't need "internet knowledge" for iPlayer, don't be so melodramatic.
It's just basically an app.  If you can use an app on a phone you can use an app on the TV/Firestick/<insert device of choice here> where there is no need know anything about the internet.  It just needs a connection.

Well it depends on what you mean my Internet knowledge. If knowing what to do if your router stops working is Internet knowledge then yes you do need it.

No more so than needing "antenna knowledge" for when your TV aerial or dish fails. If you're not very technical you're calling someone out anyway. If you have Virgin or Sky or BT TV they'll sort it themselves, otherwise it's getting the phone book out (until they do away with those too since 99.99999999% of people do it online)