I have a special pump that I use to suck out engine oil on boats. It is electic but you can buy a cheap hand pump at marine places or Harbour Freight.
I first stuck the suck hose in the rad and drain it..Then I remove the hose at top of motor,in the picture below the coil. turn the heat control to hot and stick hose into the rubber hose coming from heater core and it will suck the engine block almost dry.All coolant is being pumped into a 2 gallon bucket.
I then remove lower rad hose from rad and suck the remaining coolant from that hose. When done mabe 1 pint may fall into bilge.
There is a drain at bottom of rad under the rad hose but is very hard to get at.
Anothe way is to jack front end of car up a but. Pull lower rad hose of and let drain into bilge. and out threw water drain in hull.
but alot will stay in bilge that will have to be flushed out with water.