Next steps for you would be:
- Write the architecture.
- Simulate the design
- If the output does not match what you intend AND you have attempted to debug the problem then you should:
- Post the code you have
- Write up a description of what the problem you're observing (Hint: "It's not working" will not produce any useful feedback from the group)
If "sequential" means actually a sequential circuit, counting sequentially in time, there must be a clock and probably a start signal. Or do you mean a sequential description of an asynchronous circuit, e.g. using a for loop?