Amounts per taste, find the balance that suits you.
I usually use an entire stalk of leek, about two apples, a tin of beans (rinsed), a small jar of small capers (drained) and about a cup of gherkins (on the sweet side).
Chop as you like, mix, leave for about 15 minutes, eat.
I cut the leek into half length-wise and then slice, so you'll have half-circles, but you can do full circles if you like. I chop gherkins quite finely.
This salad has two strong tastes: leek and capers. If you don't like oniony tastes, this isn't for you. You can leave out the capers if you don't like them, my 7 yo daughter doesn't...