Complex sentence: He helped organize the Vilnius Conference, and was elected to the Council of Lithuania, signing the Act in 1918, and then served in the organizations working to establish democratic institutions in the new state, including the Ministry of the Interior.
Split into simpler sentences: He helped organize the Vilnius Conference, and was elected to the Council of Lithuania, signing the Act in 1918. After independence Šernas served in the organizations working to establish democratic institutions in the new state, including the Ministry of the Interior.