Adjusting the truss rod controls how high your action is, meaning, the distance between the strings to the fret board. You wouldn’t want it to be too close because the strings of the guitar would rattle. Having them too far away would makes the strings too hard to press down. This varies from guitar player to guitar player. Look in the sound hole you should find the truss rod there. Use an allen wrench to adjust, and remember - righty tighty, lefty loosey. This little blurb about adjusting your action via the truss rod is not meant for beginning guitar students. Most competent guitar teachers should be able to make these small adjustments.
* And by all means, please go to a qualified repair person for more serious problems .
Jack R. Baker