I recently came across an application for suse. Its a dock bar similar to mac OSX. I want to install that application. But I dont know how. What commands am I supposed to use generally to install an application?

First, always use the package manager and repositories if at all possible. It will be in your menus under "yast" or maybe "install software"--or something similar.

In the package manager, you can do a search to see if your app is available. (You may need to select repositories and/or refresh the database.

If it is not available in the repositories, then the installation will depend on the particular program. Does is come as an .rpm?.... or maybe .tar.gz ? If it is .tar.gz, first unpack it using "tar -xzvf filename", then cd into the folder created. There will usually be some kind of README with instructions.

I went through the readme file. It said "make install" and "make menu", etc. I tried them all. But couldn't install it. I was getting errors. The software isn't so necessary for me. I just wanted to try installing a software by giving commands in the terminal.

A good starting point can be this sticky thread. Regarding the installation you've tried, maybe you encountered an unmet dependency, that is when installing from source the code you're trying to compile need some other code (e.g. libraries and include files) or need some other software already installed on your system to properly run. In general these informations are available on the README or the INSTALL file or - even better - in the web site of the project developing that particular piece of software. You have to go through one step at a time. If something doesn't work on the
step, you should investigate what is missing on your system. When the configuration is successfully completed you should go through the
step, that is the actual compilation and see if there is any complaint about missing header files or libraries or any other kind of error. After a little of experience you will be able to recognize where the problem resides and look for a solution. If you want, you can post the relevant issues about the installation you're coming through and see if someone can help to figure it out.