Although this has been highly regarded by some users,
as a complete beginner to MDX I am finding the tutorials very difficult to follow.
Honestly, I wouldn't start here as a complete beginner. The book "SQL Server 2008 MDX" will help you build a solid foundation. "Practical MDX Queries: For Microsoft SQL Server Analysis Services 2008" has a lot of good drills to reinforce the syntax. For me, it took getting use to the rules for creating sets on the axes before getting familiar with all the things you can do with calculated members (as discussed in this stairway). These sets (of tuples) define the context for the cell/calculated members evaluation.