Lay concrete foundation for a bike shed

Remove turf and a footpath of paving slabs and do a porcelain patio approx 16 ft by 14ft, bordered by sleepers on 2 sides and with a step approx 2metres by 600mm up to house. Put some more turf to extend lawn at bottom of garden (approx 3ft by 12 ft). Remove weeds from an area approx 12ft by 3ft, then lay membrane and top with bark.

I have a steep and overgrown section in my garden that i would like levelling and landscaping