MDX: Changing a SELECT to a Cube Calculated Member


Not sure if this is the right place for MDX, if not could you point me to a good forum.

Just starting my journey on learning MDX and I have worded out a select which works OK but having trouble changing
it to a WITH MEMBER and then into a Cube calculated member.

I have this on my test cube which runs OK.

SELECT ([Measures].[Amount]) on COLUMNS,

[MyBudget].[MyBudgetName].&[ThisYear] *
[GL Account].[GL Account].&[1658 - Sales],
[GL Account].[GL Account].&[1657 - Concession Sales],
[GL Account].[GL Account].&[1452 - Web Sales],
[GL Account].[GL Account].&[1526 - Sales (Licensing)],
[GL Account].[GL Account].&[5985 - Royalty]

FROM [TestCube]

I want to just have in my cube a new measure which is for [MyBudget].[MyBudgetName].&[ThisYear] and the GL Accounts listed , I've tried various ways on the select above but I'm getting Error#.

Could you point me in the right direction on how to work this out, what to search for on the net, tried searching for With Member Dimension filter but no luck