Our Requirement is to display Product (say Product A and Product B that is our Article Types). When I click on Product A, it should show it's Category(Cat1 and Cat2, this is our Data Category). If I select Category 1 it will redirect me to another page :i.e. Questions. On this page I want to show a search functionality which will search for an Articles and if I didn't found the Article then I want to show button 'Raise a Case' to user. Can we achieve this using OOB functionality on Community same like below salesforce page?If not OOB how can we implement this?
So here Topics = Article Type, Category = Data Category and Questions = will search for Knowledge Articles.
What you are referring here is necessarily a Path component that you want to utilize it on your Community.
The answer to your question:
is both Yes and No.
Yes because, you can achieve this functionality OOTB as long as your are using the standard Path component and that you have a supported Object. Refer to more on its documentation.
There's also a lightning:path (available with API v41.0 and is still in beta though) component available where you can customize your custom lightnings. This component also utilizes the Path metadata as setup for your object.
No because, you seem to be using Article in your case, and thus you cannot use the standard Path components here. So you have couple of options here which you can implement.
You can have a custom object to define the Path metadata and use it along with your use cases to display details for specific stages on your community uitlizing lightning:path component. This will allow to render the Path component while utilizing OOTB features and enabling you to handle further details.
Utilize SLDS Path process component to build a complete custom implementation. This approach will require much more writing of markups.
Ultimately it will depend on your design approach and how you build it, but you definitely have options here to get started in that direction.