In order to open the Bio-PEPA perspective you should go to Window Open Perspective
Other (see Figure 63). Then you should select the Bio-PEPA perspective (see Figure 64).
Sometimes a wrong click of the mouse can close useful views that hold information which you need. The fastest and safest way to get back your views is to go to Window Reset Perspective (see Figure 65). Then, click Yes in the dialogue box that appears (see Figure 66).