I recently made an effect (5th gear overdrive) but I don't want to try it yet because I'm not sure how well it's made. It may have not-so-good soldering or stuff like that.
Is there any chance of me frying something and if there is, what would I most probably fry? I'm most worried for my guitar .

As you can see in the title, I'm new to electronics (relatively because I do know how to solder, having gone to an electronics "club-thingie" - not a very good one, hence the name -  ,although I'm out of practice. Actually I wasn't very good at it to begin with ).
I read most of the posts on "the newcomer's forum" and tried to do the 5th gear overdrive but was not very successful. For one thing, how do I connect the jacks to the whole thing? They each have 2 electrodes(I think) and in the schematic there's only 1 wire coming out from or going into the jack. The jack in actually has 6 plates(3 pairs): I'm guessing that one pair is for one electrode and the other two are for the other.
And another question: are the 3 lines, each progressively smaller that the other equivalent to a downwards pointing arrow, meaning the ground (that's the (-) isn't it?)?

   Since this is the newcomer's forum, i thought it would be ok to ask these questions. I apologize if otherwise. Thank you in advance.