multivalve question for spring startup

2 quick question for spring startup concerning my multivalve port:


1) I changed my sand this winter. I know I have to prime my pump. Can I leave it in the backwash position to prime it so no "sand" will get in my pool? Or does it have to be in the "filter" mode to prime my pump.

2) My pool is solid green. Should I shock it first and have it in the "circulate" position? I heard if you startup your pool in the spring in the filter mode it will get your sand filter really dirty.
I was going to shock the pool in the "circulate" mode for a day then put it in the filter mode. Is this right?

Thanks,