Setting tempo

Hi. I must be having a brain storm. How do I set the initial tempo and keep it there? I seem to be getting in a right mess trying to do something very simple. I write the names into the score [Allegro or what ever] but when I go to play they do not work. The first bar is good but then every other bar plays back really slowly. I am importing a mxl file.
Many thanks.

It sounds like you might have fixed tempo mode enabled. Click the note value in the mini-transport in the toolbar so that it’s illuminated. Dorico will then follow whatever tempo marks you’ve added in the score.