I have no experience in modding Sins, but I do have experience in modding Dungeon Siege and Supreme Commander.

maybe I can help point you in the direction you need to go. 

some file can simply be opened with notepad or the text editor of your choice. other files are compilations and require special tools to open/extract or at least rename the file extension before you can access them.

Now I don't know the file structure of Sins but....

in SupCom .lua files can be edited with whatever text editor you choose, the same with .gas files in DS. they are simply single files and can be easily opened/edited.

but then we have .scd files in SupCom, they are a compilation. they need to be renamed to .zip first, then you can open and extract the files compiled within for editing, .lua, etc... and when done renamed the root folder back to a .scd so the game engine can read it. easy enough

then you have files such as .dsres or ds2res files in Dungeon Seige that require special tools to extract and recompile. these actually required 2 special tools to mod, they call the .dsres/.ds2res files tanks and required a "tank viewer" to view/extract and a "tank creator" to recompile after modding. it was actully easy to do you just have to find the tools. however this is and example only, these tools will not work for sins, they were made for DS only.

if there are any special tools required usually the game creator will provide them for the modding community if they support it. If the game creator does not support modding then you may still be able to find a hack utility that someone has created.

so that said, the files you opened that look like mumbo jumbo, are probably compilations that need to be renamed to something like .zip or need a tool to open/extract. so try that first (renaming), if no then find a community site for sins that has a dedicated modding forum. they will know exactly what you need. 

like maybe here