time varies with a cycle.depending on the temp of the water,size of tank.etc...i have a 10 gallon.temp set at 78 F it took almost 4 weeks.i did it with live fish..the more media u have the better.like gravel,decor,plants,things like that..but on average it can take about 6 weeks.
u will need a water tester kit,i recommend API freshwater master test kit..
u will need to check ammonia,nitrate,nitrite,ph....adding fish food will keep ammonia in it.as long as you are adding fish food the cycle will continue.but as to when it ends you wont really know unless you have the test kit.if you dont have a test kit.and cant get one.id let it run for 6 weeks..
you can also take it to a local pet store and they will check your water for free most likely.
keep adding food to it everyday as if you are actually feeding fish.so feed your pretend fish and let the tank cycle :)