Production order settlement - Make to order scenario

hi experts.

i'm getting Error message . while doing settlement in ko88 (processing type - Automatic)

Define a settlement cost element for receiver type SDI

Message no. KD506

Diagnosis

In allocation structure A1 (controlling area P001), you did not define which cost element should be used when settling costs/revenues of the sender. Nor did you define receiver type SDI.

Procedure

Assign a different allocation structure to the settlement sender (-> Master data -> Settlement rule -> Go to -> Settlement parameters), or maintain allocation structure A1.

if i need to create cost element means, under wat category, i have to create

where i should assign this???

give me some solution ???/

thanks in advance