how do i pkay mandrakes

should i send them into cc, pr are they more shooty?

Both. Pop them into play next to stuff like the background Devastator and shoot and attack them.

Most people consider them more shooty, but I consider one of their strengths that they are so versatile.
When fighting a shooty army, first shoot and then go into melee to stop them from shooting. When facing a melee army shoot. When facing lots of low t low armour people: shoot and melee. When facing high armour shooting is usually better.

Drop 'em in, shoot 'em up, then charge! But for the love of god, make sure you consult the Power from Pain chart before you bring them in! I made the mistake my first time in my eagerness to shoot up and out of position Character and I paid dearly for it. If you bring them in on Turn 2 you can reroll their charge, and if you bring them in on Turn 3 you can add one to their hit rolls in CC!

They clearly have a profile that's intended to be used both as cc oriented and shooting oriented.
The question is : what can they shoot at, what can they fight against ?
They are good at shooting : elite units where the mortal wounds will really shine.
They are good at fighting : low armor enemies, or low number enemies.

With proper positioning mandrakes can take out pesky characters trying to hide in the back (if the opportunity comes up).
In general, they are great for grabbing objectives and disrupting backfield units.

I typically bring them in turn 3 when they are hitting on 2s in combat and can re-roll charges. I typically set them up somewhere in my opponents back lines to help disturb his plans and to take out softer targets that he has protected.

You use their shooting to put some mortal wounds on that devastator squad in the backfield, and you charge to tie up that Pask or Leman Russ(or any other source of scary weapons that will take down a Ravager). You can also use them to shoot and charge to pop that bubble wrap of Guardsmen/Conscripts sitting around the heavy weapons or pask or whatever.