After login redirect user to their own dashboard

Hey there,

I have read through every post referring to this issue and it seems no one is able to provide an answer that works like most of us need it to.

Let's say our imaginary friend Sally creates a website on my multi-site network: sally.getbranded.me.

I place a "member login" button on the hompage of getbranded.me and Sally goes to login.

Once she logs in she is taken back to getbranded.me, but she needs to be taken to sally.getbranded.me/wp-admin.

So how can this be accomplished? Thanks!