The simplest method is to use the Content Manager program (click Content from the Trainz Simulator 12 Start Screen).
When Content Manager starts click the My Content tab.
Find your layout in the list.
Right mouse click on the layout name and select Save to CDP...
Select a disk drive, a folder and give the .cdp file you are about to create a name and then click the Save button.
.cdp files are the same as the ones you download from the DLS.
You can combine several different items, such as a layout route and all its sessions, in the one .cdp file by holding down the CTLR key as you right mouse click each asset name in step 2 above.
