Reading electrical schematics and connecting relays?

Hello,

Is here on the page a comprehensive explanation on how to read car schematics and how to actually connect/use existing car relays?

Thank you

There's typically a key at the start of the schematics manual that explains what each component is and how to use the manual. I'll admit they initially can be a little daunting but if you persevere they start to make sense. What you'll often need to do is trace a particular circuit across multiple pages though in order to see where it actually terminates.