I really love this bike, I've had it for a few months, I know it's nothing special, but I had a Californian Mongoose when I was a kid, and got this for cheap. I know it's not a great bike, but I like the frame and it's a fun ride to and from work.

What I need to do: replace the bottom bracket, the crankset, and the chain.

I found a Bucklos crankset that I'd like to get for it, but I'm not sure on the bottom bracket. I can't find anything regarding what I would need to get in terms of size for it. I was hoping someone here could give me an idea of what I need. I haven't replaced parts on a bike in a long time, I remember how and have done it many times, but that was 20+ years ago lol.

Any help would be appreciated. I know I could just go out and get a better bike, but I'd like to make this one work for a while.