Once you start COPASI, you are greeted with the COPASI Logo on the right and COPASI's Model and Task tree on the left where you can select the individual elements of the model, the tasks etc.

If you select the item called Model in the tree, COPASI will display the model dialog to the right of the tree. On the right side, you can see the settings for this model, which are the name of the model, the units that copasi will use in the model and a description of the model. Here you should give the model a more expressive name and maybe a short description.

For a description of the other settings please have a look at the COPASI documentation.