'Basic electronics' resources
From zero to Arduino (maybe a HOWTO someday?)
Rule zero:

Don't overestimate the other Arduino users! They all were not born with this knowledge too.
Never be too shy to ask!
Making mistakes is ok as long as they trigger learning.

(-: short break :-)
You'll find lots of HOWTOs and other tutorials in the wild wild web.
I assume, the confusing thing is to read them in the wrong order.
Forget your Arduino(s) for a while and start with reading about:

General common components (resitors, capacitors...) and when and how to use them...

This will at least partially answer:

Safety rules, what happens when you do something wrong
How to read schematics (different elements that appear there)

If not already done:

Read about ANDs, ORs, NANDs, NORs, FLIPFLOPs...

This will show how their schematic symbols look like.

...compare them to creating the same behaviour by programming (if,
and (&amp;&amp;), or (||), ...)
Have a look at bit operations (&amp;, |, ... on whole number variables.

The programming up to this point can be done on your PC.
After this, dedust your Arduino again and jump into:

What different pins are used for (yeah, even on a more basic level
than arduino documentation)

(Happy end. At least for now.)
(I make this a community wiki answer to invite others to expand this text.)