When using finder:

Return is for renaming, not opening files. To open files press cmd + o.

If you want to preview a file (basically super quick opening for review) hit space bar. If you hit space bar again it closes, or you can use the keyboard arrow to see the file to the right, to the left, up or down. This opens images, pdfs, presentations and documents.

To send a file to the trash, hit cmd + delete

Open a new finder tab, it’s just like in a browser with cmd + t, close it just like in a browser with cmd + w

Close applications with cmd + q, close windows (app instances) with cmd+w. Let’s say you have two Word documents open simultaneously. If you just want to close the one currently focused, that would be cmd+w, if you wanna close Word, that would be cmd + q (easy to remember because one is q for quit and the other w for window).

In most apps, save is cmd + s, save as is Shift + cmd + s.

When you’re working with text, cmd + right arrow or cmd + left arrow jumps the cursor to the start or end of the line, ctrl + right or left jumps one word forward or backwards. If you add shift to those two shortcuts is the same but selecting text. Oh! If you want to forward delete, hit Fn + Delete (this is what windows calls delete as opposed to backspace).

So, basically, keyboard shortcuts are different and as soon as you get used to them, you’ll become way more fluent in MacOS, same goes for trackpad gestures, they’re super reliable and the experience with the trackpad is superior to the experience using a mouse, so try it out.