There's a drain twist plug (black--sorta hard to see) on the front bottom of the radiator on the passenger side. There is also an overflow tank under the bed behind the driver. The mixing coolant ratio is 50/50.
Pictures Hi, These pictures came from a Japanese site - the are of a newer Sambar Van [late 90's?]. Being that the engine and rad are at opposite ends you have to drain in two spots I would say. 1st & 2nd pictures show rad drain and coolant being drained from rad In the 3rd & 4th pictures they have a pipe disconnected from beneath the front wheel. In the last picture they have a hose/ pipe disconnected at the engine I would say to drain the block.
There is a drain plug threaded near the oil filter pointing down (empties block end). As for the plastic drain valve on the radiator I'd avoid using it. Why? If it breaks you're replacing the radiator. Remove the outlet hose (bottom radiator hose) on the radiator to drain.
