How to set 2 priorities aperture & shutter-speed on Rebel T6 ?

[Dianoban]

Camera & lens: Rebel T6 & EF-S18-135mm f/3.5-5.6 IS STM

I am going to take pictures of elementary school kids. They are moving constantly and the ambient light, shine, cloudy, rainy and shadows, is also changing rapidly.  I need an aperture F11 for a reasonable depth of field and 1/250s shutter speed for freezing the motions.  Can F11 and 1/250s be set up on Rebel T6 simultaneously and how, please?

Thank you.

[Tronhard]

With respect, I disagree on the basis that the OP's parameters are basically flawed.
I think they need to set a scene that offers minimal real-time light variation, with no direct sunlight: it's bad practise as subjects are either back-lit or likely to squint.  If you check out my post I can demonstrate that a much more open aperture will provide sufficient DoF while allowing enough light in to cover any movement.  In that respect, I think that Av mode is most appropriate, especially if they use auto ISO set with a max of 1600.

[deebatman316]

Tv (Shutter Priority) Mode isn't appropriate for the OP's situation. It would be best to use Av Mode with an aperture of F/4.5 or F/5.6 when I was still shooting with an APS-C camera. With Full Frame I usually shoot at F/7.1 or F/8. Stopping down too far would result in unintended things (distractions) being in focus. Which is something you would want to avoid. F/11 is unnecessary for what the OP is doing. Using Auto ISO with upper and lower would be a good choice too. Unless the OP is using flash whether that be built-in or an external speedlite. The camera will ONLY use ISO 400-800 in that case. That's how Canon's DSLRs work the EOS R series cameras don't behave this way. A lot of times it will push the ISO as high as ISO 3200 or even higher.

[normadel]

Why is Shutter priority not appropriate? The OP's concern is wanting to stop the action of elementary kids moving around. There's a certain minimum speed needed to do that.

[Tronhard]

The OP is also concerned with Depth of Field, which is why they are looking at f/11 as an aperture. 

As I have commented, I believe that limiting both to specific values is severely and unnecessarily limiting their options and making it hard for themselves.  Given that, one has to step back and leave their assumptive values aside.  For a subject group the size of a school class, depth of field is likely the biggest issue, and as I demonstrated in my lengthy post, an acceptable DoF can be achieved using a much smaller f/value, yet still yield a hyperfocal solution.  By opening up the aperture and using an auto ISO of modest range, they have much more flexibility to deal with movement and changes in light intensity - given the parameters I mentioned for location.

[Tintype_18]

What is the policy of taking the pictures of the kids? Some schools prohibit taking pictures of kids...period.  Only exception would be for regular class pictures. Check with the school or school district. Parents permission needed?