Idiots guide to electrics please

Hi All,

As you will gather I am a complete novice. I dread numerous threads about Lee tricks but they assume an entry level of electrics..... I'm devoid of this!
So I want to install a radio and new temperature gauge. But when I read the threads I see things like run a able to the battery add a relay in,take an earth to the negative etc...... reading it it makes sense but bloody bell how you do this it blows my brains.
So I'd really appreciate some advice, point me in the direction of threads videos etc. A assoc would be installing an electric fan the video shows how to fit it then simply brushes over the fact that a live cable is taken back to battery etc

Help and idiots guide is needed please.

Thanks

Alex

Here is an idiots guide, starts with basics and a good read,

https://www.landyzone.co.uk/land-rover/tutorial-car-electrics.245168/

Cheers