If the data you want to access is already available on the internet, you can easily bring it into InfraMarker if you have the link.
To do so, select the project you want to add the data to. It will show you a list of datasets that your project currently has. Click the upload button on the right hand side, and it will bring up the upload dialog. From the upload dialog, you can paste the URL's or links of the data that you wish to upload. Usually, this will be a link to a zip file containing the data so that all needed files will be uploaded as one.
This will create a background job that will download the data, extract it and begin processing any datasets that were found.