Text and Numeric Dimensions
Text and Numeric Dimensions all have a similar structure to the one below.

Below the Dimension node you will find the ‘All’ Member which is the parent of all the Members in a Dimension. Clicking on the <
> icon will reveal all the Members of the Dimension.
The ‘Filters’ folder contains all the custom Filters saved for the Dimension.
Date/Time Dimensions
Dimensions containing calendar Date/Time Members have a slightly different structure because they contain Members from multiple levels: Years, Fiscal Quarters, Months and Days.

Each of the Level nodes contains Members that represents time periods within that level. Clicking on the <
> icon will reveal the Members of the dimension in that level.
Apart from the level containing the explicit data Members (April 2007, May 2007, etc), it also contains Member ‘expressions’ whose value is determined at the moment you use them (Last Month, First Month, etc).
Each level node has its own ‘Filters’ folder, where custom Filters for that level are placed.