Install the limit switch at the back of the X carriage with M2x14mm screws
Do the same at the side plate at the side where the drag chain will be. There are pre-tapped holes.
Then at the back-side of the Wide Makerslide and at the Y axis makerslide, you’ll put in screws where the limit switch can bump into, you need M5x16mm socket head screws, 9mm spacers and a post-insertion T nut for that:
And also on the side of Z axis plate with M2.5x10mm screws. There are pre-tapped holes.
Then connect the 2-wire cables to them, depending on the indications that they have (X, Y or Z):