Nothing wrong with a cheap, refurbished laptop. Hopefully it has a warranty of some sort.
First thing is wipe all the crap off. The amount can vary dramatically depending on where you got it.
Then go through and configure your windows settings. This is pretty personal, you can just play around with most of them, but probably stay out of advanced menus if you don’t know what you’re doing.
Then start downloading free software you’re going to need. The very basics is an unzipping program and your web browser of choice. Beware windows defender, the default security software with windows, is intended to work specifically with their browser, not other people’s.
Then start downloading optional software you want. Steam, discord, crap like that. Start installing and configuring the settings of the programs one at a time.
Here’s some other people’s opinions. I haven’t watched these, but the sources appear reputable: