Hi Juliet,
I am not sure I understand exactly what you are asking. I think you are attempting to create a new dropdown field that would be associated with the CRM_NewLead Screen. If this is the case, then you would have to first create the new "Business" DropDown field in the table that is associated with the CRM_NewLead Screen. So, for this screen the table would be Customer, so in Customize->Tables/Fields, edit the Customer table. Add your "Business" Dropdown Field here, during the edit process (Step 3 of 3 when creating a NEW dropdown list) you have the ability to add your dropdown items here. Also keep in mind, whenever you create a new dropdown field, it actually creates a screen with this same name. So, once this is complete, and you find that you want to add more items to the dropdown list, you can go to Customize->Screens Tabs, then locate your new screen, which in this scenario would be called "Business". Hover your mouse over the Business Screen name, then click View. From here you have the ability to add more items at any time. I hope this helps, please reply here if you require further help, or if I am misunderstood your question about what you are requesting.
- Ben