radio and dash lights problem

Hello all im new here and could do with some advise.

im no mechanic and so need lay terms please.

Today after a 12 month wait my dad attempted to connect wires for a tow hitch electrics to my octavia estate mk 2 a5, the towbar is a Whitter and we got the electrics dig from their site.

The 7 way relay gave no power and so dad wired them (scotch) to the correct colours as advised, before we were finished we noticed the radio had died and we really dont know where the fuse is or how or even if this is the problem?

Also i now have a permanent dash light for airbag, what can i do to fix this?

I cannot afford to pay skoda, my dad is a mechanic but he doesnt know whats wrong, i need my radio back!

many thanks to anyone who can help me.