Yamaha DTXpress/DTXplorer/DTXtreme

Hi folks!  I am new to this group and e-drums.  I recently purchased 
the DTExpress II, don't have it yet, it's on order.  I ADDED an 
extra pad for anx-tra tom, and the bell cymbal pad.  How can I 
hook this up, I understand I need a "Y" jack cord, and extension 
jack cords to plug them into th 9/10 outlet.  Can anyone tell me 
what kind of plugs/jacks I will need, I think it's 2 stereo into one 
mono...or vice versa...and where can I buy these cords?  Also...can 
anybody give me any tips on the set up of this set...advice and if 
you are happy with this set?  Any help will be appreciated.