A sample slider for Simplex Theme.
Note: required jQuery Framework is already included at the bottom of Simplex Page Template.
If any of Modules that you are going to use requires or adds additional jQuery Framework, remember to either remove jQuery Framework from Module template (for example Gallery module) or to move {cms_jquery} tag in Simplex Page Template to <head> section of template if needed.
All current Browser come with some kind of Developer Tools (usually F12 key) or you can also install Firebug in Firefox or Chrome, if some JavaScript function doesn't work your first step would be to open Developer Tools and look into console errors.