taking a bottle of 1 liter of apple juice 100% that is, and regular sugar, and bread, does it take a full 7 days to brew? and does shaking it up and microwaving while burping every few hours speed the process up? also whats the correct amount of bread and sugar to use for say a liter of 100% apple juice?
Regular apple juice often has preservatives that will prevent fermentation. Check the label. When you say "bread", do you mean "bread yeast?" While bread yeast will ferment and produce alcohol, it will not make the best tasting beverage. If you can get hold of some wine or beer yeast, you will make a better tasting product.
As to the question of how much sugar, that depends on what alcohol content you want to end up with, and how sweet you want the final product to be. I'm not sure what the alcohol tolerance of bread yeast is, and it is the tolerance that determines how much additional sugar you can add. With wine yeast, you can probably add up to 80 grams of additional sugar, and it will still ferment completely. More sugar than that will probably end up making the final product sweeter, rather than higher alcohol.
How much yeast? One small packet will be more than you need for 1 liter.
I would leave the juice at room temperature. Warming it might make it ferment faster, but will also encourage the development of harsh flavors. And if you warm it too much, you'll just kill the yeast. Shaking will help only if a significant amount of yeast has fallen to the bottom of the container. Do not seal the container completely, or it may explode. I suggest covering the top with foil instead, or getting a "fermentation lock" and an appropriately sized rubber stopper.
How long will it take? It could be done in a couple days. If you've used a wine or beer yeast, you will know that it's done when the yeast settles to the bottom and the liquid becomes fairly clear. If you've used a fermentation lock, it is done when the lock stops bubbling.