Advice on my first bike building project please

Hi as you can see this is my first post, i'm a total newbie to the world of bikes, well since i was a kid anyway.

But i'm wanting to ride to work approx 7 miles (very hilly kent 7 miles) and have decided to build a bike from scratch, well almost scratch i did have an old bike rusting away in the garage but to be honest i'm quickly finding out not much will be savable.

Anyway after picking up a new frame on ebay and some other bits im getting started, bits i have so far are:

• claud buttler urban 400 frame
• two 700cc wheels from my old bike
• shimano gear and brake levers
• shimano brakes (in the post)
• claud buttler seat and a seat suspension seat post
• cassette sprockets from my old bike

What i dont have is the following:

• handle bar
• handle bar grips
• front forks plus (bit that joins the forks to the handle bar)
• seat post clamp
• crankset
• Derailleurs (maybe salvageable from my old bike)

So basically im looking for advice about what to buy, i dont want to spend a fortune but at the sametime i understand if you pay peanuts you get monkeys.

I'm having the most trouble understanding what forks would fit my frame and wheels and i'm not sure what exactly i should be looking at or avoiding?

(the bit the fork goes through measures approx 40cm diameter but everything i see advertised is for smaller tubes 1-1/8 inches these would all be the wrong size right??)

Once the bike is finished ie ride-able i might look at adding a rack and metal mudguards so anything i buy now should be compatible. Also would it be possible to find something to meet the above that also has some kind of suspension in it?

So thats the main part i'm struggling with right now but apart from that all the above that i've not yet bought i'd be happy for advice on?

Thanks in advance