Your task comes in three parts.
Of these, the most important is understanding the question of what a QTL is:
a quantitative trait locus – a genetic locus that influences a quantitative trait
The second task is getting a working R system up and running on your workstation.
The third task is using the software. You probably want qtl2, which has an free, online full-day tutorial, for which you will need to
- Understand fundamental genetic principles
- Know how to access files not in the working directory by specifying the path
- Know how to install a R package
- Know how to assign a value to a variable
- Know how to apply a built-in function
This site will be able to help you with your installation questions (please start a new topic). Although there may be members of this community who understand qtl2, you will find a more focused site here on the topic.