This is a clone of the Green Ringer pedal by Dan Armstrong, on which the popular Tentacle is also based. On its sound, Musicians Friend describes it well:
It "can have a single note played into it and will produce a second tone one octave above the original note. If two notes are played into it, it will produce sum and different tones just like a ring modulator. Depending on the musical interval between the two notes, the additional tones the Green Ringer produces will be harmonically related to the original notes (such as sub octaves) or dissonant."
It "gives the musician much better control over the effect produced than a conventional ring modulator," since they are "no longer playing against an arbitrary modulator frequency."
There's really only one non-obvious thing to be aware of: when your guitar cable is plugged in, the pedal is using power. Unplug it when you're not playing.
Instructions are written for the absolute beginner; This kit is perfect to dip your toe into the "DIY guitar pedal" waters.
Post to Reddit r/diypedals, the DIYstompboxes forum, or the Facebook Guitar Pedal Builders group. If I see any posts here I'll jump in and try to help.
You can also email me directly but you'll get a quicker response through those groups.
There are dozens of other DIY pedal communities as well, so of course you can seek help anywhere else.