If your company library is currently hosted on a cloud storage provider (e.g. Box, Dropbox, Sharepoint, OneDrive, Google Drive etc.) the best way to go about transferring the content over to Pickit is to first sync the relevant folders with your computer locally. When you're done, set up the collection structure at Pickit as you want to have it with collections/collection groups that reflect your folder structure.
Then go into each collection, click the "Upload Images" button and open the respective folder on your file explorer. Multiselect the images in the folder and press "Open" for them to sync with Pickit. Repeat the process for each collection you'd like to transfer over to your company library on Pickit.