Make sure that you are in the counter directory that you set up previously. You should soon see design analyzer come up. Now that it is up, just read in the file by clicking on read in the file menu and then clicking on counter.vhd in the dialogue box . Read both analyzes and elaborates a vhdl file. Now design analyzer will print out some stuff that will be meaningless to you right now.
Lets optimize it.
Click on the yellow symbol to select it. It will show a dotted outline if you get it right. Now go to the tools menu and click on FPGA Compiler . This will bring up a pop-up menu that will remain on the screen. Now just click on Optimize in the pop-up menu.