I am trying to queue the packets of a process so I can use libnetfilter_queue to modify them. I know that I should use --pid-owner processid to filter packets of a process and iptables -I <table or chain> <match specification> -j NFQUEUE --queue-num <queue number> to add them to the queue. However, I am confuse what value I should use for table or chain and match specification . Because I am new to iptable, I have read the documentation but still I am not sure what value I should chose, as I want to queue the packets of an application regardless of its source and destination. I would appreciate any suggestions that can help me to understand these two fields in a better way so I can select the right values for them to address my problem. 
Filtering and queue the packet of a process using iptable
iptables;netfilter