The Advanced settings include the possibility to set up a proxy server. This is described in Network configuration.
The default location is used when you import a file without selecting a folder or element in the Navigation Area first. It is set to the folder called CLC_Data in the Navigation Area, but can be changed to another data location using a drop down list of data locations already added (see Adding locations). Note that the default location cannot be removed, but only changed to another location.
The standard URL for the BLAST server at NCBI is: https://blast.ncbi.nlm.nih.gov/Blast.cgi, but it is possible to specify an alternate server URL to use for BLAST searches. Be careful to specify a valid URL, otherwise BLAST will not work.