I am new to Linux and using Terminal. If I open an application within terminal, I noticed that it renders my terminal session to be unusable and I can't enter any more commands.The Terminal session is focused on the task of running the application only. Is there a way to bypass this or do I just have to wait until I end my session with the process.
There are a number of ways that you can continue working.
If you opened a gnome-terminal via CTRL-ALT-T you can choose File from the top menu bar and then choose to open a new tab or a new terminal window via the menu or with the shortcut keys with SHIFT-CTRL-T or SHIFT-CTRL-N respectively(while gnome-terminal has focus).
If you've opened a terminal session with CTRL-ALT-F1, you can switch to another with CTRL-ALT-F2 through F6.
Another option is to background the task as you launch it by placing an & at the end of the command for example
dd if=infile of=outfile &. you can string commands by putting a double ampersand between them.
ls /home > dir.file && du /home/Downloads for example.
Of course placing processes in the background requires a way of handling background tasks. the
fg PID command allows you to bring a process to the foreground. you can obtain the PID with the
jobs command more information on handling background tasks can be found here
you can also use nohup and disown as mentioned in the other good answers here. Differences between these approaches are discussed here