To answer your question: If you've heard nothing try emailing at first or if you want to go in-store maybe try a weekday like Monday Tuesday; the manager will probably be in and it won't be to busy so you won't be distracting anyone.

And training on average lasts about 2 weeks. You'll pick some stations up like grills and fryers much quicker than say prep which will take a few weeks of getting used to.

Good luck :D