Your beef should look like this

Add your spices for the marinade

Give them a good mix and let them sit for about 15 minutes

In your a pan, add a tablespoon of oil.. Add in your marinated beef strips

Let them cook till all the water dries up

Add in your garlic and onions

Let everything cook before adding your tomatoes and bell peppers...check your seasoning

Serve with a starch of your choice