scam alert
From looking at the website, I don't have anything good to say about them and their price gouging and unprofessional content is alarming. What they offer is worth at best $10 in parts for a sale price of $168.02 is unethical IMHO.
If you did not get a schematic with the kit, I feel sorry for you and shame to anyone who advised you to get this DIY kit. They also have linear circuit DIY kits for $269 . (obvious scam)
e.g. they mention here a pre-biased NOS FET, which sounds amazing as this is a fake identification that does not exist, except on other sites that reference the same parts NOS FET meaning "New Old Stock".
The circuit will most likely contain a "JFET biased pre-amp" of dubious quality.
My only advice if you have one is to ensure when soldering the parts, that solder flows thru the plated thru holes incase they are bad. This only takes 3-5 seconds with a clean iron tip while applying solder. No more than 5 seconds.
Then avoid this site as it is a scam DIY kit site. Amazon and Ebay have much better completed boards for 10% of this cost.