It's good practice to use a search engine when you don't know what something is or how to do something. That way you don't have to wait for me to explain and I don't have to wait for you to answer.
Hybrid sleep: when Windows suspends to RAM it also hibernates, meaning that it saves you memory content in your storage, in case there is a power loss and you can still wake it up from hibernation and you don't loose your work. https://duckduckgo.com/?q=windows+hy...t=brave&ia=web
To check for background processes and memory usage open the task manager and search through the panels. You'll know when you've found it. https://duckduckgo.com/?q=windows+me...brave&ia=about
You didn't install anything or made any changes to the settings?