Hi CHARLES88,
I don't think you will have much trouble at all. There is a spring that goes between the switch lever and the switch you will need to be a bit careful with but other than that I think it will be a pretty straight forward repair. Here is a link to the parts diagram...
Link to Ryobi RY41002 trimmer.
The spring you need to be aware of is item #8 on the parts diagram.
Good luck with your repair!
-UtahAV
-Mark