Congratulations on coming home, welcome back, and God bless.
Be at peace and while awaiting your appointment, pray the act of Contrition and Psalm 51.
About your question, you don’t need to give too much detail or exact numbers.
Let’s say you viewed tentacle porn 714 times and masturbated each time.
You could just say “viewing pornographic material very many, perhaps hundreds, of times, and impurely abusing myself all those times.”
Or let’s say you did impure acts involving a dog and peanut butter 44 times, you can say “impure abusive acts involving a creature of God several dozen times.”
Or you are prone to road rage but have no idea how many times you flicked the bird to fellow travelers, you can say “getting angry while driving many times, and some of those many times making obscene gestures.”
Sins must be confessed in the Roman Rite by kind and approximate number. The kind is more important than the number - be specific enough so the priest knows what the sin is, but don’t worry about gory details - if he needs more, he’ll interrupt and ask.
And the main reason we confess the number is for the priest so he can better counsel you and see which sin you are committing most, as well as assign an appropriate penance. It’s not because God doesn’t remember the exact number of times you sinned - which is why saying “very often, many times, hundreds of times, etc” is acceptable.