Note that this will only remove the latest version of a chapter. If you wish to remove the entire chapter please see the page found here.
Select the project, click on the "Chapter" menu then select "View/edit chapter":
Click on the chapter name:
Click on the "Chapter" menu and select "Delete chapter version".
You will see a list of the different chapter versions:
Note that you can only delete one version at a time, and you can only delete the latest version. You also cannot delete a chapter version that is checked out.
Click on the "Delete" link - you will be asked to confirm.
The chapter version is now deleted and the previous version is now the current version.
If you do not see a link labeled "Delete" (as above) it is because the chapter is currently locked by a user. If you need to unlock it please see the page here for more information.