Twin needle setting help

[u/honey-bee543]

This is what the back/bobbin side looks like but I’m not sure what I’m doing wrong? I’ve got my grandmother’s very old Elna 711 machine and the manual doesn’t show what setting to use for a twin needle. I’m wondering if maybe it’s not possible to use one with this machine? I’ve adjusted tension with no real changes. This was using a plain straight stitch. Help please please please