Lots or houses in Skyrim are not required, but they are great fun additions to the game. You can set up anything from a kitchen to a trophy room on the lot you have purchased. There are three lands available for purchase in Skyrim, which are Hjaalmarch, Falkreath Hold, and The Pale. Bundles are only available after you purchase and install the Hearthfire Expansion (DLC).
Steps
Part 1 of 2: launch the game

Step 1. Install Hearthfire, the Skyrim extension
Visit http://www.elderscrolls.com/skyrim to purchase the game, if you haven't already.

Step 2. Launch the game
Find the game icon on your desktop or in your application directory and double-click it to open it.

Step 3. Once you have started the game, travel to a town
It doesn't matter which city you go to.
Part 2 of 2: Buy land

Step 1. Wait for a messenger to approach you
The messenger should tell you he has a letter for you. This will be the letter informing you that land is available for purchase.
These lands are Hjaalmarch in Morthal, Falkreath Hold in Falkreath, and The Pale in Dawnstar

Step 2. Go to Morthal, Falkreath or Dawnstar
Choose any of these three cities: all three will have their Jarl and their respective quests that you will need to complete.

Step 3. Enter Jarl's Mansion in your chosen city
Once inside, talk to the Jarl and you should be given a quest.
In Skyrim, you will not be allowed to buy a house / land unless the Jarl recognizes you

Step 4. Complete the quest the Jarl gives you
Once you are done, the Jarl will name you his / her Thane. You will now have the rights to purchase a portion of land under the jurisdiction of the Jarl.

Step 5. Ask the Jarl if he has any land they are selling
The Jarl will confirm the auction of the land. The Jarl will then tell you to go talk to his chamberlain.

Step 6. Speak with the Jarl's chamberlain
You will now be authorized to purchase the land.
Each land costs 5,000 gold and you will need to travel to its location
Advice
- For each land, you will need to complete all the quests of the Jarl who reigns over those lands.
- Each piece of land costs 5,000 gold.
- Unlike houses, you will have to build a house on your own land, which means that once you buy a lot it will be empty and you will have to build a house from scratch.
- If you helped him during the Civil War, the Jarl of Morthal will give you a small number of quests to complete in order to become a Thane.