Also going by memory (since I did not write it down), but this is what I used for the marinade:
⅓ cup vegetable oil
¼ cup lemon juice (Or you can split it with 1/8 cup of Lemon Juice and 1/8 cup of Apple Cider vinegar)
¼ cup soy sauce (I would probably use a bit less next time)
1 tablespoon Dijon mustard
1 tablespoon Worcestershire sauce
½ teaspoon minced garlic
1 to 1½ pounds of Sirloin Steak (cubed)
1 tablespoon Badia Andrew Zimmern Mediterranean Magic All-Purpose Seasoning
Then I marinated the steak for a day in the fridge.
The veggies were one of each of these, chopped into kabob size chunks (if you are using bamboo skewers, you may want to start soaking them in water while you prep the veggies). I used the tops and bottom trimmings from the peppers to make a Cucumber Salad:
1 Red Onion
1 Green Bell Pepper
1 Red Bell Pepper
If you are trying to avoid gluten, then I would seer clear of adding mushrooms, since they are often grown in a bed of gluten containing grains. There are some which are labeled "Gluten Free" but usually those are smaller, canned mushrooms. Squash, pineapple and cherry tomatoes would be good with this though.
Next just put everything on skewers, drizzle the remaining marinade over the veggies, and stick 'em in the air fryer at 400°F for about 10 minutes, or until they are 140°F inside (thats the same as a medium steak). You can of course add a couple more minutes if you prefer them well done (I ran them for 12 minutes and they were well done).
Add some Tzatziki sauce, cucumber salad, and opa! you got dinner.