As a first step toward using ProFit you need to see the vignettes which are available on Aaron Robotham's RPubs: rpubs.com/asgr
I would suggest the steps bellow: 1- The installation method: rpubs.com/asgr/274942 - You will find how to get R, ProFit, the Makevars file setups as well as a test run of ProFit.
2- Before doing any fit, you will be needed to play around ProFit by making some models. The vignette in rpubs.com/asgr/274701 walks you step by step through making simple one component to complex multicomponent models.
4- Then continue to the Full Monty vignette that covers ProFit end to end. rpubs.com/asgr/274423 - Source finding and making segmentation map, Sigma map, PSF fitting (Fitting a Moffat profile to bright stars and generating a model PSF) and fitting your targetgalaxy is elegantly covered.
5- If you are interested in source finding, you will find everything about the robust ProFound coming as a very high level function of profitProFound.
* The ProFound paper will be published in near future.
6- Although ProFit does many optimisations, having as good as possible initial estimates is a highway to having better and faster fits. Using 1D isophotal ellipses ProFit gives you reasonable initial guesses of the parameters. Find the method here: rpubs.com/asgr/286460
The manual covers everything in quite a lot of detail, and has examples for nearly everything, but it is harder to follow than the vignettes since it is just ordered alphabetically.
Beyond the manual, the *really* adventurous are encouraged to look at the course code itself. This is less well commented than it should be in many parts, but the R side in particular is high level, and should be fairly easy to follow.
People are encouraged to make package forks, experiment to their heart's content, and submit pull requests for bright new ideas.
I think that will do for starters- good luck profiling!