Pretty easy, providing you have the correct tools, you have about 10m2 in total, you will need bitumen primer for the concreted sections. l normally use torch on felt for small flat roofs, so basically what you need is as follows:
Tools:
Seivert Blow/Gas Torch (£70)
Stanley knife with Hook blade (£2/3 just for hook blades)
Scraper 4'' (£5/9)
Clout nails (dependant upon whether drips are required) (£2/8) normally come in bags of 1000
Bitumen primer (£8/10) 5 litre tins
paint brush
Hammer
Gas (red bottle) (26 kilo bottle £27)
Spanner (to connect torch to gas bottle)
Pair of red heavy duty rubber gloves (stops from burning fingers) (£3)
Fire extinghuisher
Material:
Sanded felt for the underlay, normally in 10 metre rolls, but you will need two rolls, normally at around £17/20 each.
Mineral Felt, comes in 8 metre rolls, you will need two of these (minimum) £20/26 each. Allowing 14 linear meters for any welted drips or upstands you might just get away with two rolls of mineral.
Welted drips and upstands are not that straightforward, this depends on whether you want a proper job done.
In theory and to comply with building regs the roof should be insulated aswell. You should be able to get most of the stuff from any good roofing material supplier in your area. Total cost around £222 worst case, this does'nt include stripping of the existing felt, which is best done with a hook stanley knife and a flat spade. Also some ready mix mortar if there is a wall to chase into, which means you would also require an angle grinder (large with stone blade).
Materials only around £142
Alternatively, you can buy the materials and pay me to do the job

Regards
Mike
Link for the type of torch required, this one has a long reach head on it, there is also a smaller one which would suit your job better, especially for the detail.
http://www.knighton-tools.co.uk/acatalog/Torch_Kits.html