How do saving plans work?

I don't quite understand how to enable it. Isn't it better to select a saving plan for a given period and you show me how much I need to pay and I would pay it?

It seems you expect me to know how much I need to pay upfront, credit the account with that amount and THEN activate the saving plan.

Right now I would like to pay for 3 months saving plan. How do I proceed? Thanks
Was this page helpful?