I use a wide kitchen island, or you could use a large table, tho the counter is a better height to prevent back strain. I mark the centers of the top and bottom edge of all three layers. I tape the backing to my counter/table with the top edge against the edge of the counter and hold it in position with painter's tape around as much of the edge as possible, keeping it taut. match the center of the batting with the center of the backing and lay it in place - if there's too much for the space, roll or fold u the excess to you can work on one section at a time. don't need to pin or tape the batting. Do the same with the top - matching the center of the top edge, smooth it all out and pin or baste the layers together. If I'm working in sections on a large quilt, I baste/pin a little more closely along the center edge so that when I move to the next section I've got a firm sandwich. un tape, move the sandwich to the next section, fold back the top, then fold back the batting, and smooth out and tape the next section as much as possible. then do the batting/top/basting and move on.
This system takes some maneuvering, but it's been working for me - tho I've never done anything larger than an almost-queen sized quilt this way.
There is also a technique for wall sandwiching using basting spray and several have commented that it works for them.