Create the TU using transaction /SCWM/TU
Press the create button
Enter TU of your choice
Enter the Carrier
Select the means of transport
Select the packing material
Select the S&R Acty Direc. Field as 1 Inbound
Green tick
You should see the TU appear in the header table
Next press the Assign Del. Immed. button
Find/Enter your Inbound Delivery number and confirm
You should see your delivery in the item table at the bottom
You will then have to create and confirm the WT to move the TU to the Check Point and then to the warehouse door.
Then try to confirm your warehouse task.