The "Pick From Drive" button allows you to directly Google Slides and Google Docs into TeacherMade without first convertng them to PDF. Click the "New" button on your Home Page, select "New Activity," then click "Pick from Drive" to begin the upload process. 

Google will prompt you to grant access to your Google Drive for TeacherMade. Then you'll be able to navigate through your documents and upload without first exporting to PDF.