How to set which Sent Items folder to use

On my phones and Outlook I have the opportunity to set the Sent Items folder as all providers appear to have different places and names for the ‘sent’ folder. In EM Mail client it appears to have created it’s own sent items folder which is different from the one my provider uses (SpamArrest.com) SO my sent items through EM Client are not showing on my phone sent items folder, or on in the web mail.

Here is a screenshot http://bit.ly/2oTbDJR

How can I fix this please?

Thanks

Roger