I really need to be able to find the bpm of a song from a script how can i do this or is it not possible
Using a script most likely not because that would require an ai.
Inside a script in studio / a server, no. You cannot obtain the wave of the audio. However, from outside Roblox you can request the asset and analyze it (using, say, Python).
Looks like a python library that can be used is: “librosa” (see this SO question: How to get BPM and tempo audio features in Python - Stack Overflow)
You can use the link on the website catalog to sample audio. You can also open the developer console and take the CDN URL for the audio. Alternatively, you can simply record audio when playing a game, however this has the potential for Licensing issues. Do not steal other player’s work for your own benefit.