Please make sure to go through the configuration as outlined in the Exact Online Integration Setup article before trying to export invoices.
When invoices are created and printed from Streamtime, they will usually be assigned a specific status, e.g. "Sent". This status is set in Setup > System Setup > Invoices > Sent Invoice. Of course Streamtime permits you to search and export any found batch of invoices you select. But it is best practice to search for these "Sent" invoices on a regular basis and export them to Exact Online. You can find those invoices by pressing the "Show Invoiced" button in the Invoice List. After the export, those invoices will get a new status "Exported".
To export your invoices to Exact Online, go to Invoices > List Invoices. When you have found the batch of invoices you wish to export, you just press the "Export" button. Then press "Yes" when asked to confirm. A popup dialog will appear asking you to confirm your Exact Online password.
Type in your password and press OK. An export log will show you the export status for each invoice:
After the export, Streamtime will prompt you to set the exported invoices to "Exported".
If any problems were encountered while exporting invoices to Exact Online, please refer to the Knowledge Base article about the error messages.