You need to know how to

1. Convert a decimal number (e.g. 17.35) to base 2 (i.e., it's binary representation), and

2. convert from binary back to decimal (i.e., the reverse).

We assume you know how to do this. Here is a web page that will help. It shows conversion to and from any base, and not just base 2. It's enough for you to focus on base 2, though once you understand the procedure you'll know how to do it for any base.

https://madformath.com/calculators/basic-math/base-converters/decimal-to-binary-converter-with-steps/decimal-to-binary-converter-with-steps