The Routing Slide
The primary purpose of the routing slide is to support the router when hollowing out the center of large rectangles, for instance, a shallow tray. This is done in a series of overlapping cuts as you move the slide from one end of the rectangle to the other. The MFS with slide will accurately control the depth of cut, but it does not seem to be intended to precisely control the x,y movement of the router--other than constraining it within the rectangle. There is no way to lock the OF1010 at a particular place in the slot, nor is there a pointer or markings to tell you where you are on the slide.
Both the OF1010 and OF1400 routers work with the routing slide, despite what you may have read elsewhere. The OF1010 requires the 30mm copying ring. The ring is a loose fit in the slot. The ring protrudes below the slide; at the end of the slot, the ring will hit the extrusion, protecting it from the bit.
The slide is a heavy steel channel. There's a lever clamp that attaches to the outside vertical surface of an MFS extrusion. Tabs in the slide go into slots on the top of the extrusion to keep things at right angles. The slide is clamped only at one end, but in normal use you shouldn't be applying forces that would deflect it. An index pointer centered on the slide's slot lays over the graduations on the extrusion.
The maximum distance the router can be moved within the slot is approximately 625mm (a bit more than 24"). The longest cut you could make is somewhat less, affected by your bit and also the extrusions.
Thanks to the index pointer and clamp, it should be possible to do a series of parallel slots, although the loose fit of the ring in the slot would need to be compensated for. More accurate results could be achieved with a guide rail.