I have a 2017 MacBook Pro with 16GB Ram, How do I upgrade to a32GB ?

Sell the computer and get a new one that has the amount of RAM you want.

It is not possible to upgrade RAM on modern MacBook Pros.

Since the 2013 models, the RAM on MacBook Pro computers has been soldered to the board for improved reliability. Later, the Boot drive components were soldered down as well.

No field upgrades have been possible for years.