You may also trade straight on charts - see Trading from Charts.
If you have more than one trading account set up, before opening the window CPT will ask you which account you want to open it for.
Each trading window (except for the Trade Log window) reflects one of the set up trading accounts and has a colored outline - the color is there to indicate which trading account the window represents and is set in Settings - Trading - Accounts.
These windows can also be opened from the Trading tab of charts, or from the ribbon menu of an already opened trading window. You may also open a trading ticket from the context right-click menu on many windows.
NOTE: There are various settings in Settings - Trading - General that allow you to customize your trading experience.