To begin with just get your bag and go walk around your AO, in winter probably you could use your plate carrier under your parka and nobody will notice it.
Besides doing some exercise you can start recognizing the area and practicing some land navigation, that will make the experience more fun than just walking with the damn bag for hours.
I try to integrate my training with other activities, for instance I joined the local mountain club, they usually go out to the hills for quick 6 hours walks, the difficulty is very easy because there are some adult women in the group, so I carry a heavy bag, I know new places, chill for a while and train my body to carry heavy loads.
But I think you should set your own goals, start taking your times walking from A to B with X weight on the bag and try to improve your times.
You need consistency, is better 30 minutes every other day than just going out 6 hours one day and then doing nothing for 15 days.
Take it easy or you'll get injured, and an injury can leave you for months without training.
And never forget to give yourself an adult beverage as price for the effort