The most important thing is always to have a backup of your data. Once that's done, you can decide to do things like creating dedicated partitions if you want.
When you're done with the installation you can check this thread:
Some things may be slightly out of date but it's good to have a rough idea of what's possible.
If you're not very familiar with Linux, just take it slow. The system should work fine for most use cases out of the box. And if you have any questions, feel free to ask!