Next we create an ethane molecule. This is almost identical to making ethanol:
Select the C-tool Click once to make a carbon atom Click again to make a second carbon atom Select Edit → Add Hydrogen And do it again: ... add hydrogen Click the preoptimize button
You need to add hydrogen twice: the first time one carbon atom was selected. Thus, the 'Add Hydrogen' command added the hydrogen to that selected atom only. By repeating the 'Add Hydrogen' command the hydrogens are added in all possible places.
Alternatively, you can, after placing the second atom, click on that atom to finish using the C-tool. In this case none of the carbon atoms will be selected and you can easily add all the hydrogens at the same time.
