How to use a NetSpend card I got at the store?

I got a Visa NetSpend card at HEB(Texas grocery store), and put $15 on it.

The woman didn't open the package.

When I got home, I opened it and put the card on my dads PayPal account on the PayPal app(iPhone).

I tried buying something with it but it won't work.

Do I have to activate it first? After I activate it will I be able to use it, or will I have to wait for the personalized card to come in?

Yes did you register the card yet?