New porch - to DIY or not?

[stoobloo]

How hard is it to install a new porch? A simple roof pitched that overhangs the front door approx 3m wide, 1.5m out from the door.

We have an existing flat roof 2m by 1.2m, supported by two posts. The posts aren't ideal.

If not DIY, would a roofing company be best or a builder, or someone else?

 

[opps]

https://www.manomano.co.uk/p/outsunny-front-door-canopy-outdoor-awning-300-x-100cm-rain-shelter-for-window-porch-and-front-back-door-clear-48001402

The above type is DIYable.