A lot of Mass Effect Andromeda players looks to the past with nostalgia, remembering the adventures from the trilogy and the main character, Commander Shepard, equipped with the distinctive N7 Armor. In Andromeda you will be controlling an entirely different character, as Shepard is dead for hundreds of years. However, you can still acquire and use the mentioned armor. How can you do it?
The N7 Armor is available from the Research Center - you can find it, above all else, on the Tempest ship (but also on the Nexus station or outposts located on planets). While there, enter the Research tab, select Milky Way research and go to the Armor group. A list of items will appear, with those you're looking for - N7 Arms, N7 Chest, N7 Head and N7 Legs. Those are the elements of the N7 Armor set.
Now you have to research the elements you're interested in (or all of them), as well as their upgraded versions and go to the Development tab to create the armor. There are two problems here. First things first, researching N7 Armor elements, especially the higher levels, require a tremendous amount of Milky Way Research Data points. Those can be acquired by scanning objects that came from the Milky Way galaxy (like, for instance, corpses of the rebels), a lot can also be gained after opening the Lab Technicians cryo pod capsule which generates 100 points of Milky Way Research Data every 45 minutes.
The second problem is getting the required crafting materials to create those items. Onni-Gel and Copper shouldn't be a problem, as you should have plenty of them from exploring (and Copper deposits can be found on Kadara and Voeld), but it's hard to collect Iridium and Platinum, two of the rarest resources in the game. Platinum can be found, in small quantities, on Kadara, but both it and Iridum can also be purchased from a General Merchant. Those will cost you a fortune, but they are definitely worth the price (especially if you are playing as a pure Biotic - you will benefit from this armor) - and the Credits are useless either way, as there aren't any good armors and weapons to purchase.
The alternative source of those materials is the process of item deconstruction. Deconstruction of items from the Milky Way (often with "N7" in their names) should give you plenty of materials you're looking for. Additionally, deconstructing an Ultrarare weapon will give you a small amount of every material, including the rare Iridium. This is by far the easiest and most effective way to acquire the necessary crafting materials.
Note - to create a full set of the lowest N7 Armor elements, you need x40 Omni-Gel, 290 Copper, 130 Iridium and 50 Platinum. You must, however, first research them - it will cost you 250 Milky Way Research Data points.