1: Choose your vegetables, preferably roots, such as celeriac, carrots, turnips, beetroot, black radishes, etc. You should use a variety and aim for a balance with about the same weight of each, apart from strong-flavoured kinds, of which you will need less, or they are all you will taste. I am thinking in particular of celeriac and radishes. Use pink rather than red beetroot if you can, otherwise the colour will be a strong reddish purple, which might not be very appealing - it's a matter of taste.
2: Prepare 2 leeks and chop. Then chop the cauliflower fairly small (a mandolin is ideal for this).
3: Peel and rinse the other vegetables and slice thinly (use a food processor) or cut into julienne sticks.