Really cool, Saied!! Couple tips; like Billl said, you can sterilize with bleach, but be careful. Mix ~1 capful per gallon (~4 liters) of cold water and rinse thoroughly with hot water. Get a lid for your fermenter and fashion some sort of airlock; you can do this with some tubing inserted into a hole in the lid with the other end in a jar/jug of water or water/bleach solution. This will allow the co2 to escape the fermenter while the fermenter is still covered. I'm sure considering your circumstances in Iran, that oxidation is the least of your concerns, but you will want to limit the amount of splashing when transferring you beer to bottles. Siphon if you can, but if you have to pour through a funnel, make sure the tube is on the bottom of the bottle to limit splashing. Oxidation will cause paper/cardboard like flavors is extreme circumstance. And last, cheezydemon is onto something, you're not limited to just adding sugar to NA beer, though I see where you're going with that. Anything that has sugar in it can be fermented; kool aid, fruit juice, honey, etc. My guess would be that in a country like Iran, making fruit wine might be the way to go. It's very simple, can be made with any juice or fresh fruit that doesn't have preservatives like potassium sorbate in it, and will make you a tasty beverage. There are some great recipes and info for juice wine in the wine and cider making forums on this site. Last, best of luck man, brew strong, commando style!! I'm looking forward to hearing/seeing your results, be sure to keep us updated.