Not much to tell about my day, but how about you?
“Расскажи как прошёл твой день”
“Tell me about your day”
“Kerro mulle sun päivästäsi”
We know сказать, to say already, but рассказать = to tell is one of our words today:
Расскажи - tell (imperative) - kerro
прошёл singular past of пройти - to pass, to go - mennä, sujua
твой - your - sinun, or in every day speech “sun”