I am not sure what your question is.
A "use tax" is a tax in lieu of sales tax, that is collected from you, the taxpayer, on items that you purchased from out-of-stat (typically over the Internet), but which you use, give away, store, or consume in side of California. That is, California is collecting the sales tax that you would have paid had you purchased the item inside the state of California.
Many states now impose a use tax on their residents.
The question is asking for the dollar amount of purchases you made outside the state that were used or consumed in California.
Please the following for California's Use Tax page for individual filers - https://www.ftb.ca.gov/individuals/use-tax.shtml
