Here's where you can download the manuals for many of the Futaba transmitters -
Right control 'knob' ?, do you mean 'stick' ?. Though I suppose if very new to the hobby......
. You appear to want to change it from a 'mode 1 transmitter' to a 'mode 2 transmitter'. Often that can be simply done just by moving the stick centering spring from one side to the other. Though I am not familiar with that particular model.
Also have a look in the - Radios forum
the Search this Forum is a handy tool if set to Show Threads.
Welcome to RCGroups.
There are loads of forums for all sorts of modeling, going to the 'front page' - http://www.rcgroups.com/forums/index.php?
and scroll down will give you an idea.
Some of the forums have 'Sticky' threads at the top with loads of helpful information.