First, you need to visit a Home Depot or Lowe's and get a couple of tools. The first is a stud finder, which is basically a magnet that helps you locate the studs (upright 2x4s) inside your wall by responding to the nails in the studs (the ones that attach the drywall or "sheetrock" to the wall's wood frame). Where there's a nail, there's a vertical row of nails, and where there's a vertical row, there's a wooden stud. You can mark the location of these studs with chalk or painter's tape.
Second, you're going to need a level. Black and Decker makes a laser level that doubles as a stud finder. My wife bought me one. I scoffed at it. Now I use it all the time. You'll probably find your studs to be at regular intervals. I'd like to say every 16, 18, or 24 inches, but houses tend to be crazy. You never know who built your dwelling or what they were thinking at the time. When you think you've identified the locations of your upright studs, you should be able to rap the wall with your knuckles and hear the difference. Hollow sound = no stud. Solid sound = stud. As long as your shelf supports go into a stud -- into solid wood -- it should hold. If it's going into wallboard, even a spreading anchor that distributes the weight of the shelf will probably fail under the stress of polystone's weight. Then you'll lose your statue, and have to learn how to patch a hole in wallboard as well. If you've any doubt whether you've found the stud, "explore" by tapping a few short nails in and find the edges. Nail holes are easy to patch.
Relatively inexpensive open shelving can be found at either of those same big box stores, or any similar chain hardware store, already finished in a few different colors. A nice, finished, 48" white shelf deep enough for figures goes for about $35 at my Home Depot. That's a pretty long shelf. One that could use three or four support brackets. If you find that your studs are not at regular intervals, and you want it to look symmetrical, you can use one of those spreading anchors, but the majority of your supports need to be going into wood. If the wall won't allow it, use a different wall!
You can select from the big triangular supports in wood or metal, or the less-obtrusive pelican brackets, which look very small but grip the top and bottom of the shelf like a clamp. Whichever you select, make sure they are solidly anchored in the wood studs behind the wallboard. And use a level to be sure your brackets are aligned. Don't measure from the floor. Floors aren't level.
Get your brackets where you want them and level before putting up either end of the shelf. The longer the shelf, the more it will show the slightest bit of slope, and the more supports you'll want to use. Before you buy parts, check the installation instructions for weight limits. Use the length of screw recommended. Make pilot holes first to keep them absolutely level. That B&D laser level is really helpful in this situation, and you won't have to worry whether your level is long enough. The laser beam will cover the length of the wall.
And a power drill to make small pilot holes for your wood screws, and big holes should you need to put a spreading wall anchor in, will be a big help.
As long as tools aren't too specialized, you'll never regret investing in a tool. They last for years, and open the doors to all kinds of projects. When I die, I expect my death certificate to list cause of death as "home improvement."