One of your first tasks in Mount and Blade 2: Bannerlord's is to rebuild your clan. There are different things you need to accomplish to do this, from earning Denar to recruiting troops. You'll also need to hire a journeyman, but the game is a little bit detailed on how to do this.
To hire a companion, you will need to find a town large enough to have a tavern. These will be designated on the map as large castles with a few exterior walls. Double-click on the city to enter, then click on the “Go to Tavern District” option. From there, choose to visit the tavern itself.
When you get to the tavern, holding down the left Alt key will highlight any characters you can talk to. Talk to them and you can choose to learn a bit more about their history or just ignore it if you wish. It's worth talking to them for a while, especially if you enjoy playing through the game in a more role-playing style, making decisions, and talking about NPCs based on a certain personality type for your character.
You will have the option to hire them, and it cost us around 1000 denars to hire our first companion. They'll say they have debts owing, so you can choose to hire them either, or head to another city to see what new companions might be available.
Now, it should be noted that in order to move from mission to rebuilding your clan, you will need to complete all the objectives at the same time, so if you have more than 2000 denar and used some of it to hire the companion, you will need to earn money to advance the quest.