You don´t need Studio - this is independent from the game, u have to use the ingame character creator.
I can´t post here a full creator turotial - google for "HS2 creator tutorial" and u will find some Youtubes that help.
A short introduction: first make a Backup of your card in another location in the case something goes totally wrong with your changes. In the Main screen choose "Create" and then "Girls" (if your card is a girl
) - you´r landing in the Creator screen.
Here you can change everything on your card what you want (I usually tweak nearly every downloaded card to my taste).
Open Settings, hit Load, find your card (this card should NOT admitted in a group!) and open it (loading tooks a while depending on your hardwarepower and Size of the card).
I show you as example to change and rechange an Accessory.
View attachment 1668746
Here at 01 is the wedding tiara Suzie wears in her hair.
WARNING: do NOT DELETE 01, only activate the next accessory (its Wedding Veil), wait til it shows up, then the Wedding Tiara back again. Now the Tiara is updated to the mod u have in your Repack.
NOT to delete an accessory is for the reason most accessories have to be positioned by hand for the right place on the character. This can be a little tricky and when you delete, this work is lost and you have to reposition again.
View attachment 1668775
Saving: go back to Settings and hit Save/Delete; if you have the card not inside a group, you have the option to "Save (Keep Card)", and confirm overrite. When the card is inside a group you don´t have this option, a "Save" or "Save New" resets all the characters existing stats to zero.
Read regularly this thread to learn from the questions and answers other members are posting.
By the way: if you like Suzie, one of my few self created cards, look here
https://f95zone.to/threads/illusion...lect-2-card-sharing-thread.44248/post-7310534
Learn and have fun