The endcaps with the 1/2 pvc pipe adapter works better than the bottom bulkheads because they don't get choked out by the root system near as fast. The caps were designed by me for tight tolerance on the downspout they are a little hard to get on but they will fit. Step 1: cut your downspout into the length you would like for your system. They come in 10 ft sections so most people with the room either keep them 10ft or in half to make 5ft sections. Step 2: dry fit all pieces together in the configuration you want before glueing.
Step 3: apply a bead of silicone around the end of the downspout and fit your end cap to it do not use tools to force it you should be able to get it on with just your own hands. The best way to to get one corner in first and work your way around without binding it to much. Same process for the 1/2 pvc adapter endcaps. Apply silicone to the 1/2 pipe and let dry.
Step 4: let the silicone dry for 24 hours before introducing water. Vinyl downspout and the silicon not included. These are made to order i keep a small stock on hand but may need a few days to print your order.
Turn around time may be 3 - 5 days. This item is made of pla.