Maybe it's just me, but it's my contention that the RAS requires more setup and adjustments than any other shop machine. Besides the initial table setup, there are rotating, pivoting, up and down, locking and rolling things to tend to, especially with a used saw.
I've gone through many saws and I find their alignment is a step by step in an order. One small discrepancy can throw off several other functions. Initially, there are several setups that are used by both the amateur and professional. The setup can be as a stand alone saw with it's own table. Or, it could be a saw that fits into a space with tables on both sides. Or, it could be a saw with a continuous table from some distance to the left to some distance to the right of the saw.
Keep in mind that there may come a day that the table in front of the blade may need replacing. The base framework of the saw will usually have an "L" bracket built into it to fasten the table. Some will have fixed nuts, some will just have slots. As for depth of the table, the depth doesn't have to be much more forward than the front of the arm. Having an extra deep table can be uncomfortable when working over a long period of time. As for height, I prefer a fairly tall table (at least 42" or more). It makes for a more stand up position.
The table/fence/back section sizes are a critical setup. The fence sits in between the front and back piece and its placement will determine how far the blade will be forward in the "rest" position. This is important because cutting 3/4" material puts the top of the material lower to the blade than say 10/4 (2 1/2") material. For the ability to cut thicker stock, the fence has to be more forward for the blade to clear in the "rest" position to slide the stock to the fence.
The fence height isn't that critical but should be tall enough to make or buy a sliding stop. I've always left the fence loose in its placement and held tight by the back piece. That way it can be removed easily and replaced when damaged and it will eventually get damaged.
Knowing where to place the fence is pretty easy. While doing these setups the saw should be UNPLUGGED until it's time to make the first cut. Without mounting any table parts, take the board you will be using and slide it to the left side of the blade while it's sitting on the frame below. Lower the blade so it is just deep enough to penetrate the board 1/8" to 1/4". In that position, place your tallest material you think you will be cutting, and place it in front of the blade, so there is clearance. Then place the fence material to it. Then measure from the back edge of the fence to the front of the support arm for a distance. This will give you the size of the deepest
back piece you will need. If you only allow for cutting stock that is 1" tall, spacers can be placed between the stock and the fence for blade clearance in the "rest" position to clear thicker stock.
In fixing the pieces to the saw frame, some saws have a fixed nut under the support bracket, others have just holes or a slot. Place the three pieces on the frame with the saw raised to just clear the table ahead of the fence. Mark 4 or more mounting holes.
Remove the table from the frame. Using a spade bit, bore the mounting holes deep enough for the head of the bolt to clear (that could be 1/2"). In the pilot hole drill a 5/16" through hole. A 1/4" bolt will fit through, to be bolted to the frame. Replace the table to the frame and bolt on.
Loosen the table bolts just enough to be able to nudge it. With the table set, slide the fence to the left of the blade, and set the back piece tight to the fence with the set screws in the rear. With a try square or a machinists square set the bevel of the blade to 90 degrees. With a true framing square held against the fence, set the height of the blade so a single tooth (mark it with a red marker) skims the top corner edge of the square. While pulling the saw forward you can adjust the swing of the arm to track the square. With shimming the underside of the table, you can adjust the table so the blade tracks parallel to the table, front to back. Then rotate the blade 180 degrees and do the same with a single tooth (you could mark this one black), and see if your tracking is the same.
Then, once all that is done, tighten the table bolts, and move the fence over to where it goes, and tighten down. Double check those three adjustments. Then pull out the saw to the front, plug it in, turn it on, and lower the blade to penetrate the table and slowly push to the rear to cut through the fence. It would be beneficial to place the square to the fence and check the cut line in the table as a final look. This is the way I set up for a 90 degree cut, and making sure the arm is parallel to the table.
Just a few ideas after setup, to draw lines parallel to the cut in the table and up the face of the fence to show a "no fingers" spaceway. Or, a quick spray pattern in red paint at least 1" on either side of the cutline. It may sound like overkill, but it's your fingers. When cutting stock check the table to fence corner for dust and cuttings that may keep stock from seating tightly to the fence.