in theory you can flip them off immediately after booting, however, sometiems it seems the xbox calls from the bios while xbes load, so its best to load raincoat then flip thr switches off right before you flash
as for tutorials, there are soooo many out there, and each one caters to a different audince (those with exploitable games, those with access to a modchip, those with nothing but a pc) so in a way they are all necessary, but things move so fast in the modding scene stuff is outdated in a matter of months, sometimes less