Varnishing front door

[Heinz]

Hi,
I would like to do this front door, which actually is a double door with glas and iron work. The woodwork originally has been varnished, probably stainded and varnished as the color tone appears to be of yellow ochre to orangy type. The door frame is included in this work. I like to know how I best go about to remove the old varnish, which partly looks weathered. Which are the proper steps to be undertaken to produce a good job, please? Greetings from Heinz