Hello there Cuong .... my name is roma - im one of the few women on this forum - vietnam is an extremely important friend of india and increasingly so in the very near future especially while you are about to experience the prc-dragon navy in the SCS disputing your ownership of the islands there - actually even the Hainan island should belong to Viet Nam , but the dragon is occupying it "¦. So you live in Ha Noi , it used to be called Hanoi in the past in English I think
While I might not have any information about the particular question you asked, I have an idea which I think might help you "¦.. try some search engines , then ask us for information round about that "¦
The main points are 1947 to 49 - the ccp was more interested in overcoming chiang kai shek - 1949 - 1959 ccp was preoccupied in taking over Tibet - 1959 - 1962 ccp was preparing to attack India while pretending to be a brother - 1962- 1965 is an interesting period because Pakistan took the 1962 fiasco war to be a sign of Indian weakness and it encouraged them to mass troops at the border in preparation to attack India , 1967 ccp attaked India in the eastern border , similarly in 1968 after that they mostly desisted and were more occupied in countering the usa's activities in south east asia - until 1975 when the viet nam guerrilla army won the war .
So the main activity of PLA during the time frame that you have chosen was indirectly helping Pakistan by keeping India tied down on the eastern part of Kashmir and also the eastern border areas near sikkim
another suggestion is that your topic is called " the china factor " and it is not limited to military only - so you might like to explore the diplomatic, strategic and industrial angles as well - what prc did in those indirect ways - also the prc supported the outlaw organizations in the north -east of india .... the term " the china factor " is an open term and so keep your options as open as possible .....finally as others have wished you good fortune in the endeavour , similarly from me too ....