Hello everyone,
I want to create a custom slider nav like the following picture, but i have no idea where to start as i am new to webflow.
Please help me, Thanks
Hi Mousa, welcome to the forum 
I suggest you start with Webflow University and learn about structure, layouts and working with the Designer.
The only thing that might be a challenge here is the navigation for the slides. Try searching the forum for “custom slider” or “custom carousel”
That said, what you basically need to do is put a slider to cover the hole page/section, and put your content inside.