How to make enemies start slow and speed up?

I’m making a game where my enemies are cubes that move around randomly. I’ve got the “AI” working but they just move at a set speed. I want them to start off slow and to speed up over time. Can anyone help me?

Please try and keep answers simple in language I’m new to doing things this way. Cheers! Here’s how I have things set up:

It would be really helpful if instead of just telling me what to do you also explain how to do it because like i said I’m new and don’t know too much on the subject yet. Cheers again. Thanks for the help in advance!

I would make a custom move to.
Grab the character movement —
Set walk speed to 0 (Or something small)—
Call AI move to or simple move to—
Then have a time line that sets the walk speed to 600(Or whatever you want) over how long you want.
That’s what I do for my smooth accelerations and deceleration for Virtual Reality —
I think you should specify how long it would take for the enemies to reach max speed, over a couple seconds over slowly over a long period of time, which I would do different then what i just said.

Yeah, I need it over a long period of time. my game doesn’t have levels or anything it’s just beat high scores and last as long as you can while the enemies get faster and faster.