Are you sure that's what the directions say? I just looked at them and this is what they say (now at least):
"Make sure the anode(the long leg) goes in the square solder pad and the cathode(the short leg)goes in the round solder pad. This is opposite of how a PCB mounted LED should be installed. This is unique only to the Tonebender kit."
On all other bezel free boards the long leg (anode) of the led goes in the ROUND hole.
Use small diameter rosin core solder - 63/37 or 60/40 are fine.
I think either 20 or 40 watts will work - but 40 watts will probably melt the solder quicker and will make thigs a bit easier.
Do a search here - you'll find tons of useful beginner info.
Thanks for the info, I copied and pasted straight from the PDF that is on the Large Beaver page ... seems the one you have is the other way around ... huh?
Anywhoo ... what confused me is that it says it is only for the Tone Bender kit yet the instructions are for LB.
Regardless, let me re-phrase the question:
How should I solder the LED in the LB kit?