Open the Playlist
Click the tempo/BPM value in the top toolbar
Drag up or down to change the BPM
Right-click the tempo value and choose Edit events to automate BPM changes
Open the Automation Clip menu and create a Tempo automation clip
Draw points on the automation clip to set BPM changes over time
Use the Pattern/Playlist timeline to place tempo changes at specific bars
Right-click the tempo control and select Type in value to enter an exact BPM
Use the Event Editor to fine-tune tempo changes
Save the project after setting the BPM changes