I think you can build that, the plans should be good enough. I personally would not build it. I think the litter tray will never be used, it has 8 nests when all you need for 10 hens is 3 so excess materials and building, and every piece of lumber needs to be cut (no standard lengths anywhere and a lot of wasted materials. That right side wall frame is ridiculously complicated, access your nests from within the coop to eliminate most of that. Most people can build sheds and houses with most standard wall studs at 16", not the different spacings on those, but a few specific cases may require different spacing such as at doors. I understand there is a lot of personal preference in this but the coops and sheds I've designed and built do not look like this.
How many chickens will this coop hold? You are in New England (thanks for that info) so there will be several days in winter that run will not be available due to wind and snow unless you block wind and snow out of it. So they will be restricted to the coop section only part of your winter. You can get a lot of different opinions as to how much room chickens need. Commercial operations have shown that they can be housed in pretty tight quarters but they often have to take special steps to keep them from cannibalizing each other. It is fairly common for them to clip off a section of their upper beak so they can't take a bite out of each other, for example. We don't manage our chickens that way but prefer to give them enough room we don't have to take those special precautions.
Each chicken has its own personality so that plays into it. If they are all at the same stage of maturity and are fully integrated they can usually get along on less space than a multi-aged flock where you have to integrate some. You may be able to keep ten hens in there or seven may be too many. If you can rig up a section of the run where you can keep snow and wind out of it and give them access your capacity goes up a lot.
I really like Dobie's idea of finding a shed already built and converting it. You'll need to add nests, roosts, a pop door, ventilation, and maybe a window. Nests don't have to be that complicated, especially if you go into the coop to gather eggs. If you decide to go that route let me know and I can show you many options. Roosts do not have to be that hard, just a board or limb hung up. Pop doors or windows can be pretty simple, depending on what shed material you are dealing with and how it is put together. Again I may be able to help if I know what you are working with.
If you must build, you might look for plans for sheds at Lowe's or Home Depot. They often have shed plans and even books that show you how to do certain building things. Another place to look is your public library. Even if they are not on the shelves your librarian can probably order some books for you. I'd look for a minimum 6' x 8', larger is a little better. 6x8 is probably big enough to get 10 hens in there and give you room to move around but it may be tight in winter.
Another possibility is to buy a shed kit at Lowe's or Home Depot and convert it. They come with precut pieces. I had my 10 and 12 year old boys assemble a shed for me so they could learn how. You and your friends should be able to manage.
For the run section, all you need is a frame with wire mesh on it. You will need a door. You can make it as big as you wish. I certainly want it high enough that I can walk around in there.
With a little help you can build a coop. There are techniques to learn in how to cut and how to screw or nail things. One of your issues may be what tools you need. Maybe your friends can help. Many people with no more experience that you manage.
Good luck. Let us know how it goes.
