Dual SIM data switcher

Hi guys, I'm completely new to this app.

I'm trying to create a simple widget with a toggle switch to change whatever sim card I would like to use for data usage.

It's a pretty frustrating operation done by hand, considering the fact that I switch data from sim1 to sim2 and viceversa a lot of time in the day.

Can anyone suggest me how can I start building my own widget?

Thank you very much

I think that Kustom (and any app or widget) have access to change your sim cards. Android don't allow other apps to do this.