1. For that you need to understand the differences between ASO and BSO.
2. With the help of wizard you can migrate , check that too.
Refer the chapter
Sandeep Reddy Enti HCC
1) you have to document clearly what is happening BSO.
2) Prepare plan how you can do the same in ASO.
3) You can use the same rule files for dimension building (if needed with small changes) and data loading.
4) Calc script- Calc all is not needed as ASO will calculate the top level members in the runtime.
5) Any formulas used in the Calc script - Try to accomodate them as MDX member formulas and thouroghly verify the data.
6) If any subset clear and load is there. you can not do the same as easy in BSO. Use report script to export the slice of the cube and use the exported file and write a rule file to insert #MI. and then load the new file.
7) once solution design is ready craete ASO application. Convert the outline using Oouline conversion wizard. Tke the snap of warnings and try to work out them.