Romanian salad, or salada de boeuf, served with homemade mayonnaise

Ingredients:
4/5 medium potatoes
4/5 medium carrots
2 parsnips
half of celery root
400g chicken breast
Home-made mayonnaise ( I will unload a video next week with how to make it.)
4/5 cucumber pickles
200g green peas
1 tablespoon bouillon Powder