I need to put several subscribers of different topics in one .cpp code

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I need to put several subscribers of different topics in one .cpp code, in short'm starting to Subscribe all topics that provide information relating to TurtleBot2 and also like to know the topics with information that should really relaventes Subscribe, I'm using / odom bringing x , y, theta wanted to bring the covariance matrix also if someone tell me how to do it, and using cmd_vel to bring the x, y, what other topics related to sensors can Subscribe and how.

Thank you