The best way is with a Park HCW-11 (or similar). The less better way (but still doable) is with a pin spanner . The least best way is with screwdriver pushing on the slots. It’s not the easiest way but will work. It’s just usually a lot of work.

A word of warning, however: If that is your bike it looks kind of new and, based on the bottom bracket, it’s on a very low end bike. Lots of those parts are made from Chinesium which is a substance that looks like steel but has the strength of wet toilet paper. Often those pull apart when you try to unscrew them and become a nightmare to extract. If you can get it out, I wouldn’t put it back. Get a cartridge bearing bottom bracket as a replacement. They are much more robust.