In practice, you need not be in the same location and the same timezone to seek or provide help. There are lots of communication tools (starting from e-mail to a collaborated wiki page) which can help you in this regard.
That said, in my opinion, first you need to work on your requirements and estimation. Given that this is a new assignment for you, it's expected that you're likely to face challenges with the overall knowledge - question is what has been done to overcome that?
- Did you receive the required induction / knowledge transfer for the assignment?
- Do you have knowledge / access to relevant documentation are you using the properly?
- Is the requirement and acceptance criteria clear enough to you before you start working on something?
In summary: Challenges are inevitable (and sometimes, welcome), you need to ensure you have a plan for that.
- Use the communication tools provided to you wisely.
- Seek clarity on the work assignment.
- Work on preparing a plan / estimation before you start actual work.
That way, you'll be able to foresee the blocker cases and seek for any help / assistance in advance which can help you overcome the timezone gap.
Finally, if all of the above still does not solve the problem, you need to find a time slot which is convenient for all and have a meeting to get this solved. You're the one asking for help, so you need to adjust the time slot based on the priority of the person you're seeking help from.