If it’s like a jquery ui type thing, then you’d load jquery and jquery ui via the define script definition using relative file paths to the jquery and jquery ui and then in the page I it add your JS and whatever other scripts you are gonna add using jquery (ask stackoverflow for example). For a suitelet, there’s several ways to go about it. If you want to just write a basic html scheme and write it when your suitelet is called, you can attach a client script to the suitelet using the form.clientModuleScriptPath and let that client script contain the jquery handlers for things like button clicks or field changes that you attach to your html via jquery or in the initial scheme itself.