Set specific field to a value from a lookup list

Hello guys,

I have a problem. I have two lists level. so I can use a workflow to connect the lists. I would to know how I could set a value from one list to the other.

I onyl need to use the Action--> Set field to current item or do I have to use additonal things oder actions?

When I start this workflow it does't work at all. No change in the field.

I hope that you can help me.

Best regards

Matthias