step 1 - is there a reason why you find 16gb ram insufficient?
step 2 - check if your laptop can upgrade ram; some models, ram cannot be upgraded
step 3 - if can upgrade, check which type of ram to get
step 4 - check product manual, for steps on how to open your laptop [note: sometimes this voids your warranty]
more details from proper website
https://www.crucial.com/articles/pc-users/how-to-upgrade-laptop-memory