how to exchange paypal to alerpay ??

That is really not possible unless you find someone who has an account with balance in alertpay and trade it with them. I think its really hard to find someone unless you really know the person, some people might cheat on you and just take your money and not give your alertpay money. Just try to be careful with it ok.

The only way is to transfer the money from a service (Alertpay or Paypal) to your bank account and then from your bank account to the other service.