Step 1: In your Weebly homepage, go to the Weebly Editor by clicking the Edit Site button.
Step 2: Once redirected to Weebly editor page, scroll down the icon tab on the left side to see if Social Media Stream is on the Installed Apps.
Step 3: Click Social Media Stream app on your Weebly editor.
Step 4: The settings of Social Media Stream will appear. Click the Tumblr icon and connect your Tumblr account by logging in your personal profile or your blog.