Questions about buying free zoom whiteboard plan

Can I buy the whiteboard plan for $2.49 a month while I am on the basic free tier plan so that I can only use the whiteboard feature and create more than 3 boards?

While I was trying to buy, it was asking me for number of licenses. What does number of licenses mean?

My expectation is that if I buy a license, then I should be able to free create how many ever boards I want, share them with other individuals and they should be able to edit those boards. Is that possible under the $2.49 whiteboard plan?