Need to know how fuel system and fuel lines are installed fuel lines dryrotted cant determine where to hook each line can i see a diagram

Line from tank with the filter on it is the supply line and goes to the carb inlet fitting. This is typically on the "bottom" of the carb (with the tank being up) and will usually have a fitting with barbs or a bulge on it to ensure a tight fit. The other fitting on the carb is the return line and is usually a straight tube fitting with no barbs. That line goes the suction side of the primer bulb. The third line goes from the outlet of the primer bulb to the return barb fitting in the bottom of the tank. Fittings have to be removed from tank to properly install the new hoses on them. Remove retainer ring on outside of tank and push fittings into tank, then shake out of the fill opening. More details on proper installation follows.

If yours is like all the Ryobi units that I have seen you just need a piece about 12" long of 1/8 ID fuel line. You can usually order that from parts suppliers or get it at some lawn and garden repairs shops. Hardware stores will not likely have it. There is a fitting with a hose barb on it that fits through the tank. On the outside of the tank on the bottom there will be a round plastic ring, assuming the fitting is still in place and just the hose split at the fitting. Use a knife or thin blade of some type to pry off ring. It is actually around the hose that is over the barb. Keep ring, you will need again. Now push fitting up into the tank. You may have to trim off the hose that is outside the tank on the barb to get it to go into the tank. Shake tank around and get fitting out of tank. You will see there is a piece of hose on it yet. Remove that piece of hose. Now take the new hose and slide it onto the barb. It must go all the way to the top of the barb fitting so that the hose actually goes into the tank through the hole drilled in the tank. The OD of the hose acts as the seal to keep gas from leaking out of the tank. You may need to put some oil of some type (vegetable oil works well) on the barb and inside of hose to help slip it on and use some pliers with smooth or rounded jaws ( no serrations, will damage hose) to get hose on. Thread other end of hose into the fill hole of the tank and out the hole in the bottom of the tank. Hint: Straighten out paper clip or use small wire inserted into the hole from the bottom of the tank up towards the fill opening. Slip tube over that and use the wire to guid the tube directly to the opening. Pull hose through the tank. When fitting with barb and hose over it reached the hole in the tank it will resist being pulled through. Carefully pull firmly on hose to stretch it so the hose/fitting "bulge" pulls into the hole in the tank. Look into tank and see when top flange of fitting is tight against the bottom inside of tank. You should see bottom of barb outside of the tank with the hose on it. Once in place put the plastic retainer ring back over hose and push up to bottom of tank. It should fit snuggly when you get to the "bulge" area. Cut hose length as needed to fit onto straight tube fitting on primer bulb. Should be good to go. You may find that the other hoses are getting bad also and may want to change them at the same time, as they will probably be ready to crack also. You can reuse filter from tank if it is not plugged, just add a new hose as described previously. Otherwise you can order a new filter with the line already on it. That line goes directly to the carb inlet barb. That barb is also hard to push hose on. Third line is from the return side of the carb to the suction side of the primer bulb. That is just a straight piece of 1/8" ID hose and pushes onto straight tube fittings, very easy to get hose on compared to barb fittings.