made some chicken broth. now to make soup should i sautee veggies first and add broth to them or heat broth to simmer and add veggies to heated stock?

I prefer to sauté first. then add aromatics and let them warm before adding broth.

It depends on the vegetable and the situation. Some of them I sauté first, others I add to the stock as is.

Generally speaking I consider the ingredients and think whether or not browning those would add desirable flavors.

There are also cases where some ingredients have flavor compounds that fat soluble and really need to be sautéed first to liberate those flavors/aromas to the fullest. Many members of the allium family -- like onions -- fall into this category, for example.

Ultimately you will have to come up with a strategy based on how you envision the end result. If you want a delicate and/or lighter soup, avoid lots of sauteeing. If you want something heartier and/or more darker soup, sauteeing will be beneficial.

I've made delicious soups in many styles from many origins and cuisines and I assure you there is no global "this is the only way to do it" generalization.

Best of luck.

I would saute veggies first. But that is the best thing about soup you can do what ever you want. Enjoy!