From 17 to 20.
17:Assign variants of posting period to company code. D999 to D999company code
18:Setting the open and close potiong period. D999 +/A/D/K/M/S 1-12 13-16
19:Define tolerance group D999 for company code D999
20. Create new document 100000000. two issues appear, but resolved successfully.
Now I am touching the first main content of FI moudle, I think so , however I finish the first document in SAP. and the next would be very difficult, I am always keeping confidence