LinuxMusicians

How can I set quantity of measures on a line? and get rid of the identation of the first line.

Partly solved. To remove the identation I found this in the online manual and it works:
\layout {
indent = #0
line-width = #150
ragged-last = ##t
}

I'm not sure if you can predefine a number of measures per line, but
you can certainly insert \break to force moving the next measure to the next line.

See http://lsr.dsi.unimi.it/LSR/Item?u=1&id=838, recently added to the Lilypond snippet respository, which allows you to specify the number of measures per line.