Queries regarding Notesnook trial, billing cycle and switching from monthly to yearly plan

[lone hamlet]

Hi, so I have been trying out Notesnook for a few days and have been loving it so far. I want to subscribe to the pro plan but unfortunately I do not have enough funds in my bank to go for a yearly plan outright. I would have to opt for the monthly plan for a month or two. I have read the TOS and searched around here but still am a bit unclear regarding this. So please bear with me.

1. When do I get charged after entering payment information? Right away or when the trial ends?

2. Which would be the smoothest way to switch from monthly to yearly plan? To cancel the monthly plan before the next billing cycle and to subscribe to the yearly plan?