Answer 1

Sololearn has some lessons that deal specifically with arrays:
https://www.sololearn.com/learn/CPlusPlus/1625/
Aswell as multidimensional arrays:
https://www.sololearn.com/learn/CPlusPlus/1629/

You can also find tutorials on the internet:
http://www.cplusplus.com/doc/tutorial/arrays/

https://www.tutorialspoint.com/cplusplus/cpp_arrays.htm

https://www.geeksforgeeks.org/arrays-in-c-cpp/

All these tutorials cover the topic pretty well, so maybe you should try going through one or two first. If you have any questions regarding arrays afterwards, feel free to ask.