Garden storage - advice on assembly

I've just bought the following storage:
http://www.shedstore.co.uk/itemlist.php/findtext/Windsor+Garden+Storage+Chest

Having never assembled a shed before, I have a few questions. Excuse me if I sound a bit clueless - that's probably because I am!

1. Position/base.
We have paving slabs in the garden that I was planning to sit this on but from doing some reading, it looks like I'll need to raise it even higher to prevent it sitting in water.
- What can be used for this? More slabs?
- Where could I source this/these from?
One issue I have is not having a car and living in London so a bit limited in transport/suppliers, although there is a Jewson up the road.

If I do raise it, is it an issue having holes at the bottom? What would people use to block these?

2. Stain/painting
I'd like something that's going to look good, last a long time and be reasonably easy to apply.
I was thinking of painting it but do I need to protect/prime it first? Is it better to stain than paint for longevity?
What are the best brands? Is there much difference between Cuprinol (which I've read good things about) and Ronseal?
I assume I should do all of this before assembling - should I do inside and out? Should I do under the felt?
How many coats are required?

3. Equipment
What exactly do I need e.g. brushes, stainer, volume of liquid?

4. Is there anything else I need to consider before I start building it?

Any help appreciated.

Thanks.

Never a bad idea to raise it up a bit. Looking at the size then probably about 8-12 bricks would suffice with a bit of damp proof membrane or felt on top of the brick. You should be able to get these from the jewsons , something like semi engineering bricks are good for this. Alternativly check out any skips that may be local to you and raid them.
As to the holes, don't block them up airflow is a very good thing unless you're a big fan of mould and rotten wood.
Treatment , the cuprinol is fine comes in several colours and will be easier to maintain than paint. Couple of litres and a 3" brush would do it fine and you may as well do under the felt , it won't hurt it.
Speaking of felt it has probably been sold with the thin lightweight guage felt that most outside buildings come with these days.It'll be fine for a while , a few years to be fair but when replacing it I'd go for the 38kg green mineral felt.

Great reply - thanks.