*buys something online*
wow it sure is good to have a reason to live again
1. On the Customize screen turn off the Use default mobile theme option under Advanced Options. 
2. Remove the stash logo from your website by getting a Full License.
3. For the Instagram feed generate your Access Token & User ID here.
4. If you still need help check out our help section or the theme documentation.
1. You can try to turn off HTTPS/Encryption in your Tumblr Blog Settings. https://www.tumblr.com/settings/blog/your-blog
2. If you customized the HTML code of the theme you may have broken it so I suggest redownloading or using Tumblr's Theme Recovery.
