I need to edit a video sound

I have practically completed it It needs finessing. its 9.50 mins long and is a talking heads over a power point presentation. I have done everything using canva and the power points come in exactly the right time for pp. I cannot get the music long enough so either you have a track of better stilll can we stick the one better together so that it transitions well. I can send you the video but realised you may not be working. today I really need this urgently by today please