Decking / Sumerhouse project

[rjm2k]

I'm looking to build decking on the area shown below, any advice on the best way to approach it? I'm thinking the planks should run towards the bottom of the picture, also there will be a bannister on the right where there is a drop and some steps bottom right, also possibly a summer house built into the area at the back which currenty has rubble on.

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There's a timber yard nearby so i expect I'll get the timber from there.

Thanks in advance.