Basically you have a sign bit, an exponent part, and a mantissa part, and they represent the number

(1-2*sign_bit) * (1.0 + mantissa) * 2^(exponent - K) where K is a constant, exponent is interpreted as an unsigned integer, and mantissa is interpreted as the bits (of a base 2 number) after the decimal point, forming the number 1.abcdefghijklm... where abcdefghijklm... are the bits of the mantissa. And sign_bit is 0 or 1 of course.