Some very important piece of advice: do pick some strong identifiers. The ones that were generally in use for test currencies are generally not strong and could potentially be hacked. Again, there is a post about it, but it is in French (and maybe it would be worth translating as a priority for us). The main advice was to choose a strong Secret Identifier along with a strong password, for instance generated using Diceware methods. Until you receive your first certification, you still have a chance to change your IDs.