Welcome to this forum!
I am looking at the motorized bicycle kit that you are planning on building. for a first build, this kit is pretty hard to install. you have to assemble the piston and all the other compenents to the engine. I would go with a kit that has the engine already assembled. there are two types of motorized bicycle engines. the first type we like to call china girl. those are the cheap no branded engines that you can find on ebay. the second type is a better quality engine like a grubee Skyhawk engine or a sd stinger engine. I wouldn't buy the kit that you are looking at. the kit is the cheap type and youhave to assemble the piston. if you just want a regular cheap type of kit, I would write motorized bicycle kit in ebay and find the cheapest one there that doesn't need assembly. the black engines also tend to look uglier than the silver metal engines.
I would by something like this>>>>>
Now, if you are looking to ride everyday (ex:commute) and want a good quality engine, I would buy the sd stinger engine from bikemotorkit.com even though the final order comes out to be around $200 with the shipping, it is definetly worth it. they are a good trusted company.
These two-stroke engines come in two sizes. 49cc and 66/80cc
they look exactly the same except for the small difference in piston sizes. companies say 66/80 cc because in china with the metric system, they count as 80cc but in usa it is 66 cc
I would buy a cheap mirror and a bicycle battery powered headlight from a website like walmart.
as for the bicycle, I would go with a huffy cranbrook from walmart. they are around $70 right now new and they are very simple to install.
as for the tools, you will need a :
a drill (you have to make a hole in the handlebars for the throttle assembly)
a 15 and 14 mm wrench (optional).
that is everything that I can remember off the top of my head.
Good luck and happy thanksgiving!!