1. Go to http://rsbweb.nih.gov/ij/download.html and download the version of imagej that's compatible with your OS and your machine (choose 32 bit if you are using windows XP).
2. Go to https://code.google.com/p/cornell-spectrum-imager/ and download with CSI 32 bit or CSI 64 bit for your windows or CSI for Mac.
3. Run the CSI file and it will unzip the files to a directory you specified.
4. Copy all the \macros and \plugins folders from the CSI to your ImageJ directory
5. Run ImageJ
6. Go to Edit -> Options -> Memory and Threats and change Maximum memory to whatever number you want.