97 F150 -drain & replace coolant?

is there a drain plug at bottom of radiator?- if not, how do you drain? does new collant mix go into the plastic reservoir ? -since there is no cap at the top of the radiatior itself - where do yo actually por the new coolant ?

No. There is no drain cock on the radiator.

To drain the system, you have to remove the lower raditor hose from the radiator. And this doesn’t remove the coolant that’s in the engine block.

The new coolant is added to the reservior until the level is correct because there is no radiator cap.

And then the cooling system must be purged of any air that may get trapped in it.