Q: Questions about storage, render files and "other"

Hi all,

I purchased my first macbook about a week ago. Recently and only recently, I've been using my Mac primarily for video editing for a few personal projects I have coming up and I've been using iMovie to do so.

I previously owned a PC and I transferred all my files using Assistant Migration. I'm not sure if it is my data from my old PC or what, but my storage disk is already full. The "other" category is taking up the majority of space; 53GB out of the 128GB of my Macbook Air.

I've used Omni Disk to get an idea of what is taking up the most space however I'm afraid to delete anything because I have not yet backed up my Mac (external hard drive has yet to come).  At first glance it seems that render files is taking up a lot of space. Is it safe to remove render files? What are they?

Specs wise, I have a Macbook Air (early 2015), 1.6 GHz Intel Core i5 and 8 GB 1600 MHz DDR3.

Now I'm stuck wondering whether or not I purchased a Macbook that does not have enough storage or that there might be a lot of unnecessary files on my Mac.

Any help would be greatly appreciated!

-M