Both "tra" and "fra" mean exactly the same thing. You can use them interchangeably to mean "between" (two places) or "in" (a certain amount of time). We just switch them to avoid repeating sounds (e.g. use "tra" instead of "fra fratelli" to avoid saying fra twice).

When giving directions to a stranger, Italians use the Formal Imperative (Lei). It often looks like the present tense but with different endings: -are verbs end in -i (giri), -ere/-ire verbs end in -a (prenda).