Help with outdoor enclosure

Hey. I am very interested in building an outdoor enclosure for my 2 and a half year old bearded dragon, Bobby.
My questions (there is quite a few, sorry)
•How big does the outdoor enclosure need to be? He is 23 inches long. His my big baby boy
•I do not wish to use any sort of glass for the sides (I've seen a picture my friend showed me) so what material could I use for the sides so he can see out of at least a little section on each side?
•what is the best type of lock or latch I can use to put on the door I will be building so I can move him in and out without having to worry about him escaping?
•I am uncomfortable with him being on the soil and grass unattended. I've heard of the illnesses and parasites etc that they can get. Could I make the bottom of my enclosure wood and just attach a reptile carpet? That is what he has been on since I got him.

If you have any other suggestions please let me know. Thanks!

Some people just use a childs playpen or a wire dog cage as an outdoor enclosure. If you're going to build one from scratch, I'd build it so there are areas of direct sunlight as well as some areas that are covered/shady. I would build it as large as you have space for but at least 4' long and a few feet wide. For the sides and top I'd use something like chicken wire or screen material which will allow plenty of airflow while still allowing beneficial sunlight through. A hinged top would be enough to keep him in and other animals out. Inside it probably won't cause a problem for it to be bare but you could put some plywood down as a floor and then put some tiles on it or even some astro turf or something like that. As long as there is airflow (to prevent overheating), access to both shade and sunlight, and sufficient fencing to protect him from outdoor animals it should be fine.

Okay thanks!