I'm really glad you like it :-) There isn't a walkthrough yet. There might be one in the next issue of the German gaming magazine ASM - though I have no idea if that would be helpful to you. Do you have a specific question?
An empty bottle isn't a problem, but you have to fill it with a flammable liquid—which you won't find in the city. Then you need to insert a rag to act as a fuse. After that, you can throw it by hand. You’ll also need something to light it with, though simply having the item in your inventory is enough. In principle, it should be doable without an incendiary device, but perhaps it really would be better to start over from the beginning. With a bit of planning, you can even get past the cornfield without using any ammo.