There are three kind of templates: Regular, Trading and Window-Link.
It defines the frames number, location and size in a workspace. If you create a new workspace with a template with two frames, the new workspace will contain two frames without content. The frames will keep the template's settings (location, size of frames). If you change the size of frames or their location and then press "Auto arrange" button, the frames will return to the template's settings.
For a trading template you can specify frame type (recommended). When you create a workspace with this template you have to give a contract. All the frames will load their content based on this contract. If you change the name of the workspace to another contract, the new contract will be loaded for all frames in the workspace.
It is similar with a trading template plus: if you have a Quote Board or a Quote Monitor frame and you select a contract, all the chart frames (if there are) will load this contract. If you change the contract in a window frame, all the other window frames will load this new contract. In a window-link template you can create chart / spread chart frames for each resolution. When a contract is loaded in a window frame, the chart will keep it's previous resolution and change just the contract.
New - add new template
Delete - remove the selected template
Rename - rename the selected template
Apply Template - apply the selected template
Cancel - do nothing