One of the easiest ways to import data through the API is to use the Bloomberg Data Wizard.
On the Bloomberg tab in Excel, click the Import Data icon. You can search for static data and data sets using the Market, Reference, Analytical, Data Sets option; for time series data, using the Historical End of Day option; and intraday data using the Historical Intraday option (bars or ticks.)
The wizard will guide you through entering your securities one-by-one or uploading from the spreadsheet, selecting the datatypes you want, defining the time period, frequency, currency, et cetera.