\version "2.24.3"

music = {
\clef bass
\repeat segno 3 {
c1 d e f
\alternative {
\volta 1 {}
\volta 2 {g1 g1 g1 g1}
\volta 3 {b1}
} % end alternative 
} % end ds


} % end variable

\score { \music }
\score { \unfoldRepeats \music }