Gifti images analysis

Dear experts, i have been recently working on a project using Cat12 tool . I have generated cortical surfaces images such as thickness and gyrification through the analysis . I would like to perform further analysis such as statistic or apply a machine learning technique in order to get some result for publication . However i found it difficult to analyse gifti format. i followed some instruction found on forum( including workbench and Surf Ice) but still get stuck can you please advise me