The Master Tempo can be updated from the Operations Tab, by clicking on the Master Tempo icon.
The operations tab responsible for actions that process or affect your score in any way
The dialog box will prompt you to enter beats per minute (bpm) which will affect the tempo of score globally. If you have tempo markings on your score, these markings will be updated accordingly as well, so you won’t have to update each marking individually.
Change the global tempo beats per minute (bpm)
You can also change the Master Tempo on the Mixer View, by clicking on the area right below the tempo slider, as indicated in the diagram below.
Change the global tempo beats per minute (second location)