I am not sure what you are asking here or where you are selecting the script from. You may be talking about the script button in CRM that opens a script and you are asking how to set that button to a specific script.
If that is correct, if you go to the page in the Sales Playbook that displays all of your script here - https://salesscripter.com/pro/folder/sales-scripts, you will have an option to select one of the scripts as your "Primary Script". Whichever one you select for that is the script that opens from the CRM.
If that is not what you are asking about, please let me know or ask your question again in a different way.