I am sooooo glad I am not the only one day dreaming about winning the lotto lol so I already know what I would do!

All the sensible things first:
I would pay my mortgage and then buy an investment property (or two) so I could rent them out so that DH wouldn't have to work as much - maybe part time so I could go to Uni and finish my degrees and the kids wouldn't need to go into care for me to finish.

Set up trust funds for the children to access at a much later date & separate education funds.

Then I would invest into my business plans so I could have something keeping the family sustained financially in the long term & just so I could finally create my dream business!!

Those items above could be done without revealing where the funds came from because no one would know that level of personal info.

And you know, all those indulgent things lol
Buy my dream car/a
Holidays! Clothes! Etc