How do i detect the player's speed?

You have x y and z velocity procedure blocks for this

I suggest you check our tutorials collection playlist on our YouTube channel which contains many examples and tutorials that can help you get started with MCreator: https://www.youtube.com/playlist?list=PLAeL-oIFIEngE6jRgFYeFMfuj8WQsO3Ei

this procedure blocks don't exist anymore... or I don't see them

so, thery is another way to get the player speed? (and set)