I am doing a trailheead exercise ahd trying to download app from  https://appexchange.salesforce.com/. Slelected to install in Sandox.
I used mydevelopment login to access the sand box. Unable to login to sandbox with development userid
a) do I need a separate user id to access sandbox ( Url --> https://test.salesforce.com)
b) what do I need to do to make my deleopment login valid in sand box.

Appreciate any quick response

I am doing a trailheead exercise ahd trying to download app from  https://appexchange.salesforce.com/. Slelected to install in Sandox.
I used mydevelopment login to access the sand box. Unable to login to sandbox with development userid
a) do I need a separate user id to access sandbox ( Url --> https://test.salesforce.com)
b) what do I need to do to make my deleopment login valid in sand box.

Appreciate any quick response