Nowadays robomongo developers releasing the new versions of robomongo as tar.gz not in .deb packages that was easy for double click installations. But
1. First Download the version from the official Robomongo website bellow:
Download Robomongo From Official website using this link
2.Then extract the downloaded tar.gz file in your downloads folder.
3. Copy and paste the extracted folder into your opt folder
/opt
NB: If you don't have permission to paste in this folder use the bellow command in terminal to access the folder.
$ sudo chmod -R 777 /opt
4. Open the opt/robomongo/bin folder and launch Robomongo by clicking the executable icon.
opt/robomongo/bin
5. Simply Create a database and right click on the Robomongo icon and select the lock to launcher option. This will create a shortcut t launch the Robomongo application at any time you need.