Hi , and welcome.
Fermentation should begin fairly soon after the yeast cells regenerate but orange juice is very acidic. Your must - the wine before you add the yeast - looks like it will have a specific gravity of around 1.090 or higher (the sugar in the OJ and the sugar you added) and that will then have a potential alcohol of about 12 % (or thereabouts). Not sure that bread yeast in that kind of acid bath will ferment the OJ dry but if it does you might find the sharpness a little unpleasant.
The only really good way to know when the fermentation has stopped is to use a hydrometer and measure the specific gravity. As long as the yeast is actively converting sugar into alcohol and carbon dioxide the specific gravity will be falling - the hydrometer is essentially measuring the sugar in the liquid. Water has a specific gravity ( a fancy term for density) of 1.000 and the density of alcohol is lower than 1.000. When you add sugar to water the density increases. When you add yeast to "sugar water" (your must) the yeast converts the sugar to alcohol and so the density drops. If your initial specific gravity was about 1.090 (approximately) then when there is no sugar left the gravity should have fallen to about .996 (approximately).
My guess is that the bread yeast will give up the ghost a bit before that (there may not be enough nutrients in the OJ for the yeast to repair their cells and the acidity may put a real strain on the yeast , while bread yeast is not "designed" to survive in concentrated levels of alcohol...OK.. but with a hydrometer if you take a reading and that reading has not changed in three days then for good or for bad the fermentation will have ceased.
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