I have 2 problems here.

1. Is it possible if "Select one or more categories" of "K2 content" can choose more categories in com_content? I mean more categories already in Joomla. Because K2 content just can choose K2 categories.

2. How can I add rss into K2 categories? I mean I want to apply rss for k2 that auto take posts from other website to my website.

anyone can help me? :(
This is the first time I have used k2

anyone? :(

Hello tai,

I am not sure you have understood how K2 works exactyl. It is a complete replacement to the Joomla! article system,

These videos will help you understand K2 getk2.org/documentation/k2class2012

As for the aggregator functionality, there are several components which support K2 posted at the JED