There are 2 options when creating a range.
1. Create a table in your DW to store the range. This approach very usefull when you have a dynamic range. Change in range will be treat like a change in fact or dimension
2. Create a range in OLAP cube. By creating range in OLAP cube, you will enforce the range as a business rule, therefore if you want to change the rule, you should reprocess the cube (full process)
To create a range that you want, simply add a calculated column in your fact table (on dsv). Use a case condition to create a range. Then create a degenerated dimension (fact dimension) from this colomn. Voila .... now you have range in your OLAP cube