To search for your cost centre you require simply click on the arrow to the right of the 'Search Cost Centres' text.
A drop down will appear, from here you can scroll through and find the cost centre you want.
Alternatively you can use the free type box at the bottom of the drop down. When searching for your cost centre you can do this on either the cost centre code or the cost centre description.
Cost Centre Code Cost Centre Description
You can then select the cost centre you want and this will load into your basket.