measures 1-7 are tempo 49 starting at measure 8 it goes to tempo 80. I have BIAB 2010. and its on windows. Thank you.
The first 7 measures will play at the tempo set in the tempo box.
Go to measure 8, press F5, and you will see the Bar Settings menu. There is a place to set the new tempo.
Right click on Bar 8. Select Bar Settings. In the upper left corner you should see 'Tempo change to' ... enter the new tempo.