Hey Julie 

Thanks for posting in the Lucid Community In order to insert your downloaded Lucidchart you can import into Google Docs by clicking Insert > Image > Upload from computer. 

Alternatively you could insert your diagram using the Lucidchart Add-On by clicking Extensions > Add-Ons > Get Add-Ons and navigating to the Lucidchart Add-On. Then you will see the Add-On featured on the right side panel and you can upload your diagram directly. 

If neither of these options works for you please let me know or reach out to us directly at support@lucidchart.com. We would be happy to help. Cheers!