A line shows a bonding pair of electrons (which are usually 2 for every line) – the atoms involved in the bond share two electrons per bond to form a covalent bond. The two dots show a pair of lone electrons NOT involved in bonding.
The Carbon and Sulfur will require to have their valence orbital shell involved in the bonding to have 8 electrons. The Hydrogens need 2 to achieve stable electron configuration. This way the atoms achieve stability in the molecule