Creating a character for the first time can be an intimidating process, but it isn't hard! Here are some tips to help you get started:
When building or generating a character, it's important to remember, you're not designing a person, you're building a character. It requires lots of pieces to pull off a good one. It is a work of fiction. Putting too much of your own personality, or playing “yourself” will only lead to bad things in and out of game. You will be too offended when people don't like you, too upset when the things you try fail, too hurt when those you care for don't respond in kind or betray you.
If defining your characters' personality is tough, try a starting point like where they're from. A history of where they've lived, how they've made money. Even a loose understanding of their origins can help inform you of what they're like.
For example, are they from a place that is focused on agriculture? How do they feel about it? Are they trying to get away from the life of a farmer, or are they dedicated to the land and looking for new things? This can help guide you towards what their families are like, what their neighbors look like, their politics, all sorts of things.
Once you have some basic understanding of their home, it'll be much easier to build out the rest of their character. If they care about the land, maybe they have some resentment to merchants, traders, or maybe they work in a market, maybe they're strong both in will and physically-- it's easy to see these dominoes fall in place.
Writing your initial character lore can be as simple as the basics just like this: Where are they from, what do they like, what do they hate, what do they aspire to do.
A single simple, basic goal can be incredibly helpful. If your characters' goal is to establish the best farm in the land, all your actions in game can be tied to this, and it can further inform what they're like.
Just remember: If you're self-conscious about your writing, you never have to share it, but establishing something for you to refer to and understand deeply will guide you for the entire game.