This configuration allows you to customize the lead stages for pre-sales user. Even though there are some fixed lead stages in sell.do, you can definitely customize lead stages by either adding stages before opportunity stage or after opportunity stage. You can also add sub-stages for those stages.
You can directly copy these stages to sales or you can configure different stages for sales
To track the reasons of lost and unqualified leads more accurately, you can add the other reasons for the stage which are responsible for lost or unqualified leads. You can do so by editing the stage.