To add one of the search boxes on this page to a guide (excluding the Google Image search box), all you have to do is click on the 
button and choose "Google Search." You can use this tool to insert a Google web search, Google Scholar search, Google Books search, or Google Patent search into your guide.
To add the Google Image Search box to your guide, copy and paste the embed code, as previously described.
Other Google widget options:
How to embed a Google Doc (Also works with Google spreadsheets and slides)
