How do i create a macro that fits (calibration of data)

I have a question please, I know it might sound stupid to proffecionals like you but I have no idea about C++
and it is taking me a while to get used to it :frowning:

We are asked to create a macro file in order to help us calibrate some data that was collected during a nuclear reaction experiment. My question is how can I specify the information i specifically need from the root tree files that need to be worked on. and how do I specify the file numbers i need my macro to plot and fit.

I will appreciate any one who is willing to assist me on this coz i am very confused. :open_mouth:

Thank you :smiley:

How to read a Tree?
How to Use Chains (List of Files)?
ROOT Tutorials: Trees I/O, Queries, Graphics
The “Trees” chapter in the “User’s Guide”

Thank you very much for the useful links