Welcome to the group!
Google has many links to 'basic' electronics.
For example Google: resistor LED
Also, YouTube has many tutorials on the topic.
Arduino links of interest.
Listing of downloadable 'Arduino PDFs' :
Either Google >>>- - - - > arduino filetype: pdf
Or
https://www.google.ca/search?q=arduino+filetype%3A+pdf&rlz=1C9BKJA_enCA739CA739&oq=arduino+filetype%3A+pdf&aqs=chrome..69i57j69i65.1385j0j7&hl=en-US&sourceid=chrome-mobile&ie=UTF-8
Listing of downloadable 'C++ PDFs' :
Either Google >>>- - - - > C++ filetype: pdf
Or
https://www.google.ca/search?q=c%2B%2B+filetype%3A+pdf&rlz=1C9BKJA_enCA739CA739&oq=c%2B%2B+filetype%3A+pdf&aqs=chrome..69i57.22790j0j7&hl=en-US&sourceid=chrome-mobile&ie=UTF-8
Arduino cheat sheet:
Troubleshooting common errors:
Watch these:
Arduino programming syntax:
Arduino arithmetic operators:
Arduino control flow:
Arduino data types:
Some things to read
https://learn.adafruit.com/category/learn-arduino
https://learn.sparkfun.com/tutorials/how-to-read-a-schematic
Language Reference:
Foundations:
How and Why to avoid delay():
http://playground.arduino.cc/Code/AvoidDelay
Demonstration code for several things at the same time.
http://forum.arduino.cc/index.php?topic=223286.0
Useful links:
https://forum.arduino.cc/index.php?topic=384198.0
Arduino programming traps, tips and style guide:
Jeremy Blume:
Arduino products:
Motors/MOSFETs
Switches:
Share tips you have come across, 500+ posts:
https://forum.arduino.cc/index.php?topic=445951.0
Debug discussion:
https://forum.arduino.cc/index.php?topic=215334.msg3823890#new