Fixed point is where the number has a predetermined number of bits for the integer and fraction like 8.8 where you have 0-255 for the integer and the fraction goes from 1/256 to 255/256 in steps of 1/256

Floating point at it's simplest just makes that a variable. So the (.) position is stored as a separate number. Now instead of being fixed - it floats around.

This way you can put more in the integer or more in the fraction.

The Microsoft Basic here used 23 bits for the number, 1 sign bit and 8 bits to say where the floating point should be placed.

Of course in practice you have to deal with a lot of details depending on how robust you want your system. This Basic was not as robost as modern IEEE754 but it did the job.

Reading more about IEE754 is a fascinating way to learn about modern floating point. I also recommend Bruce Dawson's observations on his Random ASCII blog.