I tried Mixx, but I don’t know how to work it!

Please help!

I write songs and I wanna record them, but I gotta make beats first.
And also, how do you record them?

What would be the beats per minute heart rate be of someone when they are really frightened?

Most rappers spit 16 bars a verse, but how does a rapper determine how many bars they want to do in a song? Do they just decide how many they want 2 do? If you noticed, most of the time Soulja Boy does 8 in most of his songs

I am a music producer and I would like to know where is the bestplace to sell your instrumentals apart from cdbaby and youtube and to who ?
Also how would you contact movie producers to use yout tracks like scores or jingles in their projects ? ( EASY 10 Pts )

- Thanks.

How do you make your own beats that are for free without paying for anything at all? If possible, are there any good ones that don't require installment or downloading? Please and Thank you!