No Stupid Questions

Using multiple OSes in parallel is called "dual booting" and it's not too hard to do. (Another commenter mentioned VMs. Also possible, plus is no usb needed, but you get reduced performance and imo it's more complicated to set up).

You need a blank USB stick (or one you don't care about destroying data on). You can write an ISO to it using rufus. Or if you trust enough the author's included binary blobs, you can use Ventoy which lets you multiple ISOs onto the flash drive, that you want to try on your PC more quickly. If you have a DVD drive that's a classic option, but be aware that some newer ISOs have started going past the 4.7GB single layer limit. At startup mash the F2, F9, F10, F12 or Del key depending on your motherboard maker and choose to boot your boot drive or change its boot priority up. Alternatively from inside Windows, hold Shift and click Restart, and select the option to boot from your other device.

Now if you just want to play around for one session only to do a very cursory test of the look and feel, most ISOs come with a live environment which loads into your RAM and goes away when you power down.

If you've settled on one to have more persistently, go through the install menu and select the option to install "alongside Windows", exact language varies by your distribution. The only thing to look out for is that if you see a message that says "If you continue, changes will be made to your disk", or "your disk will be erased/formatted", triple check that you select the "alongside" or "dual-boot" option because the latter message indicates that you didn't and the OS installer is about to replace Windows entirely.

This is years ago, but elementaryOS was the most mac-like in my opinion. MATE desktop (GNOME2 successor) has a "Cupertino" customization preset that mimics macOS in menu styling. However, with any Linux OS, you can get the Plank launcher (the latest version seems to be under the "Plank Reloaded" name) to get the iconic mac appbar thingy.