Hi Jrmie
Almost correct.
Maybe is better use the same type of message (polite is 3rd person, direct is 2nd person, more or less like German)
And not the infinite, you can use it to explain an action like: plan your next trip, you have translated as Pianificare i tuoi prossimi viaggi, is better “Pianifica i tuoi viaggi” or Puoi pianificare i tuoi prossimi viaggi (you can plan your next trip)
So first image: Pianifica i tuoi prossimi viaggi Aggiungi viaggi (in the interface)
For the second image maybe the right translation is too long: better rephrase it as a simple “Dove e quando?” since the argument (viaggio) is implicit from the title.
Third image ok Seleziona attivit (in the interface)
Fourth image:
Ecco la tua lista di bagagli
If you want you can send me the Lingua file, I can try to translate it (without interface and so context it can be not so easy)