You can try Widget Anywhere plugin to embed your HTML code. It works perfect without the hassle of going into theme files.
But if I found the way to add your code through Donut Theme files then I'll also update you with that (although I am not sure about this).
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.