We have the exact same dreams bed posted on the photo of the headboard. (We bought our bed 8y ago though. Similar to the photo its a base and a mattress). We don't see at all how to fix this to the bed. What are we supposed to do with he wooden legs?
The wooden struts are used to attach the headboard to the divan base. You will need two headboard bolts which you should have originally received with the divan base fixing kit.
You will be able to feel holes underneath the fabric for where the bolts need to attach. You can pierce the fabric with the bolts and and fasten them into place, lower the headboard struts onto the bolts before fully tightening them.