To get into the fourth dimension, you need to pierce a cube, or this world's dimensions, then open it up. To do that maybe you need to do it at sub atomic level? That would be a very small space indeed, so we will try to make objects four dimensional - visually.
Maybe by piercing a space, then expanding atomic structure from within that object we could simulate this concept of the fourth dimension. If you look at a cube and look into the cube, you will be able to imagine a dimension inside of the cube coming out and going around again. To simulate that we need to pierce the cube and expand a cube within the cube, then merge them into the same thing. That means tking two objects and making them the same one, not by merging exaclty, but by intersecting the dimensions or angles so that they are the same thing, while they are not, but they will be the same thing in the end.
But what about people going into the fourth dimension? They could surely have their insides turned out, so we need to be more careful. Maybe if we were to add to the human form, then intersect the objects, we could see a person going into the fourth dimension? If we were to place a human inside a four dimensional space they would enter the fourth dimension, but only be three dimensional, as in energy form they could do that - so maybe with out of body experiences they could go into the fourth dimension in out of body mode so they are not harmed?
It shouldn;t be too hard to make a four dimensional space, but is it hazardouse? Maybe try with a mouse first?