Ive just been down the SMD and purchased a few bits... brought some sports pack replica's but cant see how to fit them (no instructions

The screws dont have visable heads to tighten, ive also noticed that the bodywork is clearly visable underneath!!! When i just did a search on google all the major suppliers are trying to flog £45 templates!
How hard is it to fit yourself? Do you need you need the templates? Is there anything else to need to know before i start to contemplate drilling into my lovely bodywork

I have standard 12" cooper alloys so am slightly worried they might be dwarfed by the new arches... has anyone got any experience of having sportspack arches over 12's