Marching around the world in Mount and Blade II: Bannerlord feels a whole lot better when you can do it with a massive army behind you. When your first start the game, you can’t have too many troops under your command because you haven’t increased your worth, and not many troops will reliably trust you. However, over time, you can steadily add more troops to your clan, and you can lead them into combat. Increasing your party size in Bannerlord does take time, though.
Your party size is connected to your clan ranking and having your character as your clan’s quartermaster and having a higher skill in steward. Let’s focus on the clan leveling first.
The higher your clan ranking is in the game, the more troops you can control and have under your command. To review your clan page to see how you’re doing, you can click on the small crown icon on the lower left-hand portion of your screen to bring it up, or you can click the L button to bring it up. Once you do, you should be able to see your clan’s tier at the top right, and then you can see your current progress right next to it. If you want to increase your clan’s level you need to expand your renown, and there are multiple ways to do that, such as taking part in massive battles, winning, tournaments, and becoming a mercenary.
As the quartermaster of your clan with a high steward skill, you can steadily increase the number of troops under your command. It takes a bit of time to develop this skill, especially early in the game. To level it up without focusing on it too much when you initially create your character, you need to increase the morale of your troops by giving them a varied diet, improve your settlement’s prosperity, and spend time in your settlement and not travel as much. Providing your army with a varied diet and increasing their morale is probably the most natural first step. You can do this by having a variety of consumable food for them to eat every day, and win battles.
It takes a bit of time to develop your army’s party size, though, so don’t focus on it too much. The best way to progressively level up your clan is to go through the main story and improve your character’s steward skills whenever you can while you play the game.