How does WandaVision link Dr Strange ?

WandaVision episode 1 release 15 Jan 2021 on Disney Plus Hotstar

Doctor Strange in the multiverse of Madness will be released on 6 May 2022 in the USA 

Marvel Studios has also confirmed that Scarlet Witch will appear in Doctor Strange 2  

what could be the connection between Scarlet Witch and Doctor Strange 2  

When Scarlet Witch was reading The Dark Book in the post credits scene of the WandaVision TV series. Then She hears the voice of his children, and that voice is of Billy and Tommy  

As far as we think that voice comes from the multiverse of both of them. And then maybe Scarlet Witch goes to the multiverse to find her two kids  

Because of that, Scarlet witch gets stuck in the Multiverse or she messes something up in the Multiverse. Whose direct connection is with Kamar taj and Doctor Strange  

And it seems that there is a fight between Doctor Strange and Scarlet Witch 

Marvel DC Crossover