How is the execution of the pipeline in jenkins on the master and slave?

Question

Conveyor

In the settings, they specified vcs git, the name of the pipeline, and the lightweight flag, in the pipe work on the slave.
1. When we run the job, does it download everything to the master from the git or just the pipeline?
2. Master sends rpc to execute instructions?
3. On the slave, everything is downloaded from the git, but does the execution of instructions come from the master or does the slave itself run through the stage?
4. Are Groovy scripts still running on the master? I just know that the load on the master is crazy when executing groovy scripts, when bash commands, for example, are executed on the slave.
Roughly compiled a list of questions for the concept of path and file exchange, between master and slave, and how the work is done.
I think this will help many people to understand more deeply how jenkins works.