I have a couple of questions.
1. We created some new plants in R3 and CIFed it over to APO. After executing the product hieuristic in Product overview and PR was created, I did not find the PRs transferred to APO. I found the reason to be that I had to enter the record in 'Maintain View for Distribution Definitions' in APO IMG, I did not find the PR to be transferred. How can I transfer the PR that is already there in APO and not in R3?. I tried to re run the creation of IM for PR and activate it in R3. That did not help.
1) In IMG setting, use the following menu path SAP SCM Impl guide > APO > Supply chain planning > SNP > Basic settings > Configure transfer to OLTP systems
In this, under deployment, select the purchase requisition and say either "Immediate transfer" or "Periodic transfer". In Immediate transfer, the PR generated will get transferred to R/3 system immediately. In Periodic transfer, you need to manually control the transfer via change pointers using t-code /n/sapapo/c5.
2) Regarding your second query, you can make read of the books
a) Production Planning with SAP APO-PP/DS by author Jochen Balla, Frank Layer
b) Supply Chain Management with APO by Jorg Thomas Dickersbach
c) The SAP APO Knowledge Book by Wolfgang Eddigehausen
R. Senthil Mareeswaran.