You can backup MSSQL database from SQL Server Management Studio using the following steps:
1) Open SQL Server Management Studio and connect to the SQL Server instance where your database is hosted.
2) In the Object Explorer window, expand the Databases node and locate the database you want to backup.
3) Right-click on the database and select Tasks > Back Up from the context menu.
4) In the Back Up Database window, select the type of backup you want to perform, such as Full or Differential.
5) Choose a backup destination by selecting the destination type, such as Disk or Tape, and specifying the backup file location and name.
6) Configure any other backup options, such as compression or encryption, by clicking on the Options page.
7) Review your backup settings on the Summary page and click OK to start the backup.
Once the backup is completed, you will have a backup file that you can use to restore the database if needed. It is recommended to regularly perform backups to ensure that you have a recent copy of your database in case of data loss or corruption.