Moveing Active on it's own

hm. What's the easiest way to make an active object move in an x or y direction on it's own gradually, and be able to set this speed?

like start of frame - active gradually moves left.

or something similar?

You have a couple of options. One is to give it a bouncing ball movement, then:
Start of Frame: Set speed of object to c, set direction of object to left/right/whatever.

Another option is to update the position of the object with a new position at a very frequent interval:
Always: Set X of object to X of object + c

A step above this is using trig or an object like Advanced Direction object to plug in values and speeds to update the position:
Always: Set X of object to X + GetMovementX ("Advanced Direction Object", c, a)
Set Y of object to Y + GetMovementY ("Advanced Direction Object", c, a)

where c is some value representing a speed, a is some value representing an angle.

Then there's all kinds of other obejcts like advanced platform movement, moveit, move safely, etc that all deal with moving stuff around. There's many, many options depending on how complex you need the behaviour to be.

Thanks, I'm gonna test some of these out and see which is best for me :)