Hello and welcome to the forum.
The usual rule of thumb for the amount of housing space converted to meters would be about .4 square meters of coop plus about 1 square meter of run per chicken. I would consider these as minimums, and more space is certainly better.
What's your climate like? This will dicate what's the best kind of coop design. For example, if you get much cold in the winter, those A frame coops don't work terribly well because there's no good place to put the ventilation without letting a cold draft blow in on the roosting birds. Personally, I'm not a fan of the A frame anyway since the inside peak is such cramped space that it's hard to really use. And I really like to be able to give our flock a roost at a proper level for a bird of their kind. I think they are less stressed that way. Unless a chicken is one of those breeds that can't really roost high (like a Silkie or one of the very heavy breeds), I think they really do want to be able to roost well up off the ground. Those A frame designs, especially the tractors, tend to be quite low.
We let our flock out into our fenced backyard when we are able to watch them. They could easily fly over the fence, but they don't. The reason we don't let them out without supervision is because of predator danger. We have to watch out for hawks, and our bantams are so small that even neighborhood cats would be a threat.
We have a day tractor (a moveable pen) that we use when we can't be out to supervise the flock. This gives them the benefit of being able to scratch in and eat grass without being vulnerable. You can keep chickens in a stationary coop and run without access to grass, but it's important to make sure they have enough space and things to keep them busy. In the fall I collect bags of fallen leaves, and in the winter when nothing is growing out in the yard anyway I'll toss a bag of leaves in the run. It will take several days for the flock to investigate what might be under each and every leaf.
