Sorry to hear about your parents passing.
When there's no will, distribution for non-muslim is under the Distribution ACt 1958 amended in 1997, which states:
a) Leaving spouse and children - 1/3 spouse and 2/3 children
b) Leaving children only - 100% children
c) Leaving spouse only - 100% spouse
There are other division involving parents. In this case there is no need for me to state it.
First things first, get a lawyer familiar with Estate Administration to apply for Letters of Administration (LA) in the High Court.
Second, all the beneficiaries under the 1958 law must agree to appoint an Administrator that they choose. Get your siblings together with the lawyer for the situation to be explained to them.
Third, there is a need for 2 sureties to provide administration bond for the Administrator. This is where the law requires, the 2 sureties to provide security equivalent to the gross estate of the deceased.
Once you get the second and third items done, then there would be little else to do because the rest can be done by the lawyer. Get all the above done fast to avoid problems such as devaluation and money in the bank going to the Treasury (after 7 years).
The above seems short but in reality it may take a long time. So start quickly.