I developed a custom app in my developer org and I want to deploy it to sandbox via unmanaged package .
I created an unmanaged package in a Developer org, but I can't figure out how to install it into a sandbox
Once you get the unmanaged package link ,you will replace login with test
Lets say your unmanaged package link is
https://login.salesforce.com/packaging/installPackage.apexp?p0=04t28000000B4ng
Your package link for sandbox is as below
https://test.salesforce.com/packaging/installPackage.apexp?p0=04t28000000B4ng
Edit
Also note it takes significant amount of time for package to appear .Wait for atleast 30 minutes before pressing panic button