Scratch

Hi this is my first scratch game and i need some help

for scrolling im using the method:

when flag is clicked
forever
go to x:(scrollx+480*0 )y:0

1.Is this the easiest method because i want x and y scrolling
2.How do you make a solid object so that the ball doesn't go through
3.How do i make the ball bounce
4.When using scroll how do i make an object stay in a fixed position eg. i want to make spikes but the spikes do not want to stay in one position , it keeps following the ball
5.how do i make the ball smoothly jump.

thanks for the help in advance