Lean to Style roof trusses for an extension

[Glennhudsonuk]

Hi. I have just built a small single story extension for someone and was going to make the trusses and put them up for him by just making some triangles out of timber with the correct pitch. It is a lean to style roof.
Then I was going to use joist hangers to attach it to the existing property. Then attach it to the extension by nailing it to the wall plate and attaching the wall plate with wall plate straps.

Long winded I know, but it all seemed so simple until I spoke to building regs. Now I haven't got a clue!

Can you help with the best way to do this please? diagrams would be great!!

Many thanks

Glenn