Designing a DW solution is not easily done i a single post - there are a lots of "it depends".
If your reference is building the solution using SAS Data Integration Studio i 9.4, the corresponding tool in Viya 4 is SAS Studio Engineer.
At this point it has almost the capabilities found in DI Studio. But quite a few transformations ("Steps" in SAS Studio) are limited to nly a few source/target data sources.
Regardless, I don't recommend developing a new DW on 9.4.
What is your preferred DW database?
Other constraints, like competence - are your developers familiar with SAS 9.4/Viya?
Data never sleeps