Help Me Build My PC

Hi. My name is Lloyd and I am looking to build a better PC. The one I have is very old and slow. It is really hard to play on my current computer as it crashes frequently when I play Dota. I wanted to play other games but my PC is only able to run Dota at the lowest graphics. If you could help me out I would really be happy as I would also be able to use the computer to work at home.