What package format to download

When you want to install packages in MEPIS, search in this order (easiest/most-reliable to hardest):

if the package is available in apt-repository-list pool (use Synaptic)
if the package is available on some website as .deb file, download it onto your desktop, then right click on it and select open with 'KPackage' (or if you like the command line "dpkg -i packagename.deb") (If incompatible dependent libs occur, then do a "dpkg -r packagename'" to remove the partial-install, and then go find a more compatible .deb, or if a .rpm is also available, try 'alien' as mentioned below.)
if the package is available in .rpm format, you can install it with alien.
if the package is a .jar Java file, install it with "java -jar packagename.jar"
if the package is a .bin run it with "sh packagename.bin", if that doesn't work, make it executable by right-clicking the package, select Permissions tab and check "Is executable" (in a terminal: "chmod +x packagename.bin") and run it with "./packagename.bin" (same procedure for .sh and .run packages)
if the package is available in a tarball tar.gz or .tar.bz2 or .tbz: untar it and look for Install script (read INSTALL and/or README files provided with the tarball)
- if the tarball contains the source code, read this: Compiling