Carry out the following steps to develop a custom Lightning component and add it to an existing Home page within Lightning App Builder:

1. Click on the Setup gear icon, as shown in the following screenshot:

2. Click the Developer Console option, as shown in the following screenshot:

3. In the resulting Developer Console window, click on File.
4. Click on New.
5. Click on Lightning Component, as shown in the following screenshot:

6. In the resulting New Lightning Bundle dialog, enter CompanyLogo for the Name.
7. Enter This is a Company Logo Component for the Description.

8. Click on Submit, as shown in the following screenshot:

9. In the resulting Component page, paste the following code:

<aura:component implements="flexipage:availableForAllPageTypes" access="global"> 
   <img src="{!$Resource.WidgetsXYZlogo}"/> 
</aura:component> 

10. Click on File.
11. Click on Save, as shown in the following screenshot:

12. Now, to add the component to an existing Home page using Lightning App Builder, click on the Setup gear icon, as shown in the following screenshot:

13. Click the Setup option, as shown in the following screenshot:

14. Type app builder in the Quick Find search box, as shown in the following screenshot:

15. Select the Lightning App Builder option.
16. Click the Edit link for the Home_Page_Default customized Home page, as shown in the following screenshot:

17. In the resulting Lightning App Builder page, drag and drop the CompanyLogo component from the custom Lightning Components pane to the top of the Home page canvas, as shown in the following screenshot: