I am using the Enni theme in this tutorial, but the content applies to this section in other themes as well.
Go to your WordPress Dashboard → Appearance → Widgets.

To change the sidebar image: click the image, open the Style tab on the right-hand sidebar, scroll to Media Settings.

Click Edit Image to replace it with yours

To replace the text and button text below the image, follow the same steps explained in this tutorial .
To edit the search bar, click on it and select the Style tab in the right sidebar.

Adjust the text and background colors in the styles section.

To edit the social icons, refer to this footer tutorial here, which covers how to connect and customize your social links.
For the featured category buttons, select the button text and replace with yours, then in the General tab on the right, paste the URL of the category page you want it to link to in the button link section. Repeat for the remaining buttons.

In the Featured Posts section, you can switch between list and grid view by clicking the corresponding layout icon.

To add more widgets, click Add Block and choose what you want displayed. Don’t forget to click Update when you’re done.
