Complex sentence: Hari Bansha started his career by performing with Hari Prasad Rimal and Jitendra Mahat Avilashi in 2031 BS on Radio Nepal, then the only radio station in Nepal.
Split into simpler sentences: Hari Bansha started his career by performing with Hari Prasad Rimal and Jitendra Mahat Avilashi in 2031 BS in Radio Nepal. Back then, Radio Nepal was the only radio station in Nepal.