Script to Get all assets, and assets on next page

My script can pull assets from 1-100, but how to I retrieve 101-200, and so on and so forth.

Welcome to the Atlassian Developer Community, @afelts!

The link you provided points to Bulk create or update assets, by any chance are you referring to the Get all assets endpoint? With the assumption that you are, have you tried using the start query parameter to get the next page if isLastPage is not yet true? Something like,

GET /rest/assetapi/asset?start=100&limit=100

Hope this helps.