New to the World of Flying and need Your Recommendations

I am new to the Flying Community and intend to purchase MSFS 2020 shortly . I was told that there are some restriction that MS puts on you in the verson purchased directly from Microsoft and that I should buy my copy from Steam online.   Is there any truth to that ?    Will I be able to learn the Simulator and do some Flying with only a Mouse ?   or is a Joystick necessary ?    I appreciate all your comments and suggestions .  As I said , I'm new to this world of Flying.

THank You 
Reno1948