I would advise caution here. I've never adjusted the torsion bar (also called a truss rod) on my acoustics but have done many truss rod adjustments on electric guitars and electric basses. Always loosen the strings first and only do a 1/4 turn at a time. If you inadvertently hit the end of the truss rod travel and try to go past it, damage can result. So small adjustments, retune the strings, wait a bit and see if the neck flattens enough. Sighting down the neck you can see what is called "neck relief', or a slight bow in the neck, a little is normal. Many manufacturers have specs for each model specifying the normal relief, there is usually just a bit.
Measuring the "relief" first before adjustment is a good idea. I use a spark plug gapper.. The explanation is too long. Here's some info.
www.fretnotguitarrepair.com/repair/acous...guitar/truss-rod.php
There are other ways to lower the action, such as lowering the saddle, but amateur luthiers should leave this to a pro unless you have a beater guitar you want to experiment with-I've done this. Don't do this with your Gibson or nice Martin!
Even truss rod adjustments, a suggestion would be to have a luthier do this for you once and see how it's done properly, before messing with an expensive guitar.