Collapsible and icons Quick Launch in SharePoint 2013

I’m very new in SharePoint and I’ve receive the task to create an internal SharePoint site for our department. I searched a lot on internet regarding a way to add icons to quick launch menu but I cannot find anything from head to tail. For now I used a CSS code.

The menu shoul look like this : enter image description here

For the moment my result looks like this.

I tried to use JQuery , but again I’m new on this also. Can anyone help me with this problem ? Thank you so much for your help.

enter image description here