To import a FSB from Studio, follow the below steps:

1. Login to Studio as admin user, and right-click on 'Desktop (admin)' and select 'Import'. 
2. From the browse option to locate and upload the CAR file, or type the full path to the import file in the File field. 
3. Optionally, type a password. If the CAR was created using a password, you must type that password here. If the CAR was created without using a password, you can leave this field blank.
4.Optionally, check the Ignore Encryption Errors check box to ignore any encryption errors.

Note: If this option is used, then all backup data will be imported regardless of whether a valid encryption key was provided. This means that the import will not fail. This option can be used to allow partially importing any backed up data. However, the import process will only import data that is not encrypted or can be decrypted using the provided encryption key. All encrypted portions of the backup data that cannot be decrypted will be imported as empty values and the import will otherwise succeed.
This affects all encrypted values in the backup data, which includes, but is not limited to data source and LDAP domain connection passwords.
5.Clear items in the Include Resource Information section that you do not want to import.
For the details on the list of checkboxes, refer to the User Guide section Importing a resource
Example: If you need to import the LDAP users, select the checkbox 'Include Users Folders' and 'Merge Users Folders'. Refer to the above link for complete details on these checkboxes. 
6. Select the Show Rebinding Options box to bind a resource to an underlying source for the first time. (For details about resource binding, see Marking Rebindables.)
If you check the Show Rebinding Options box the Import Into rebinding window appears. See Rebinding an Imported Resource.
7.Optionally, click Preview to view a list of the contents of the import file without actually performing any imports.
The Preview button works like the -messagesonly option to the pkg_import command-line utility. This option displays the messages generated in a package import without actually performing the import.
Note: If the preview shows messages as - 

 Keystore "cis_server_keystore.jks" not extracted to location "C:/Program Files/TIBCO/TDV Server 8.8-9310/conf/server/security/cis_server_keystore.jks" due to error:  the keystore file:c:/Program Files/TIBCO/TDV Server 8.8-9310/conf/server/security/cis_server_keystore.jks already existed, if you want to use the keystore file from archive file, please switch it manually! Keystore "cis_server_truststore.jks" not extracted to location "C:/Program Files/TIBCO/TDV Server 8.8-9310/conf/server/security/cis_server_truststore.jks" due to error:  the keystore file:c:/Program Files/TIBCO/TDV Server 8.8-9310/conf/server/security/cis_server_truststore.jks already existed, if you want to use the keystore file from archive file, please switch it manually!

8.Optionally, type search criteria in Find, and click Search. Use the up or down arrow key to jump to the next instance of the search text. The text that you are searching for is highlighted in yellow.
9.Click 'Import' button to import the resources.
10.Click Done to complete the importing process.

Gif for reference:


Once the import has completed, at the bottom left corner you will see the number of resources being imported. 

Screenshot for reference: