In the advanced multi uploader there is a tickbox option with the description ‘initialize from workflow’ however I can’t find any element action that will trigger the plugin and open the users file storage to select files. has anyone else worked out how to do this ?
Hello, @calum.miller.work
Thanks for your question.
First of all, please allow me to note that Default value is this action is true. The best example of this action you can find on our Demo Page: Loom | Free Screen & Video Recording Software
As you can see, you upload a file in the plugin element (and it is placed in the pop-up). So, immediately after pressing on “Browse” or “Pop-up Bubble”, you initialize workflow for uploading a file.
Please check this video and our Demo Page and let me know if additional information from our side is required 
Best regards,