$1,000 is a lot, but when you're talking about suits, dress shoes, dress shirts, etc, it gets spent quickly. It is key to get Blue and Charcoal, as this will work in almost any situation and will work with blue or white shirts, giving you style options to change up your look by mixing and matching shirts with suits to make different outfits. For example, by having a blue shirt, you can wear that with both suits, plus you can wear a white shirt with both suits, so you now have 4 distinct looks, which you can further expand by accessorizing with ties, pocket squares, etc. The point is to build the basics for a beginner. You'll branch out as your needs or tastes dictate, getting not only accessories, but more suits, blazers, leathers, overcoats, etc. It will take time and thousands of dollars over that time to build a complete wardrobe. If you start here, you'll be glad you did because these will be solid choices for the next 10+ years after you buy them - no fads, here.
This assumes you have underwear, dress socks, undershirts, etc. It also assumes you have a business casual wardrobe, already. The goal here is to have something to up your game for formal dress events and formal business, such as presenting or speaking in an executive meeting, going to a funeral, going to a wedding, or dressing to impress on a night out. Some things I've left out here are ties, pocket squares, watches, tie chains, etc. (I decided to add leathers to ensure you had something formal appropriate.) This is because I would make a separate list for these, if you want to accessorize. You will need to purchase accessories as you see fit. If ties are part of the expected dress code, you'll have to buy some. But, those accessories are not essentials, in most cases. Solid yellow ties will work with either suit, as will multi-color blue/white/gray ties. As you accessorize, feel free to branch out and make fashion forward choices with those accessories.
Suits:
These can be had for $100 off on regular sales. At full price, they would be impossible to get. $700 total. Get 2-button, notched lapel, double vent, functional sleeve buttons, black buttons, straight hem legs, and belt loops for a classic look that never goes out of style.
Dress Shirts:
Feel free to replace with brand of your choice, but these are good quality for the price. $90 total
Dress Shoes:
With a 20% off coupon offered to all customers for first time purchase, these will be $160 total.
Belt:
Be sure to get a Black Leather with a buckle that matches the metal of your watch, or the metal you wish to get in a watch.