I have Lgc pro8 with a G5 OSX 10.5.8 dual 2.3 ghz. I have Symphobia and LA Strings Loaded on my secondairy HD which Im using as external because I guess my cable is messed up. So how do I get the instruments into logic studio?

Not sure what you meant about your cable being messed up, but that aside, you have to create an instrument and instantiate the relevant instrument. I'm not familiar with LA strings but I believe Symphobia uses the Play engine. So you'd create an instrument, load up an instance of Play, and go to town.