What fund should I contribute to in the thrift savings plan?

-I currently have a TSP account and am currently contributing to the "G" fund. I'm 23 years old. I know that this fund is the lowest risk fund, but also gives you the least amount of money back. I would like to know which fund gives you the most and why. I would like to hear from people who actually have one or have experience with one. I don't want to have one with a really high risk but I also don't want to have a low one either. Please let me know.

Note: I've gone on the website and read the description of each, but it's too complicated to understand. I'd like for someone to tell me in simple words. I really appreciate the help. Please no immature answers thanks.

-Mark