Please help I want to build a home pc

To all those that can build a pc,

Please help! I am a UK student getting my hands dirty for the first time in building a home pc. I currently have a mini tower and I'm starting to see its disadvantages since I'm having a lot of difficulty "upgrading" it and keeping it up to date.

So now, I will buy a reasonably sized barebone and make the whole thing myself. But how??? What goes in it? What does it need to work? What will make it a fast, efficient, safe machine to use?

I want to know what I should buy. 1. What's best... Intel or AMD? 2. What are the latest top specs? 3. What's the fastest processor out atm? 4. What can I do to prevent my computer from crashing when running lots of programmes at the same time? 5. Where to do I shop online (uk) to find these components? 6. OR EVEN, who are the cheapest pc makers out there????

I mainly use my pc for the internet, designing simple websites, processing work... I'm not a gamer and don't need tip top specs on the graphics side.

Thanks everyone!