Hi & welcome.
Winter whitewash was applied in the field, on serving vehicles, often in a hurry, so neatness wasn't needed.
Serving suggestion: (other recipes available, feel free to modify as you wish):
Paint your target vehicle as needed. Include all camo, Markings, then wear, fade, 'dinks' etc.
Some modellers would undercoat esp. German stuff with 'Rot-Braun' undercoat, then topcoat with panzer-grey or sand-gelb, then go to town with camo, markings, & wear to show a vehicle in use, then varnish to suit.
Thereafter apply the chipping solution(s) then the whitewash, in order to wear down the white to show the underlying paintworks.
Others will ahem, 'chip-in' with more detailed suggestions, how-to's etc. google youtube for more ideas.