The main focus here is on the requirements. Try to pay attention to the header names, which should be short (less than 13 characters) with no special symbols*. This nomenclature recommendation is also applied to the name of folders and files. Beyond that avoid a high number of subfolders to place your files, which can interfer in the viewer while loading it.
The data format is also a common issue, always remember to remove the air blocks, which could also be checked on the viewer. Note that a CSV file (Comma Separated Value), usually contains just one column* with all the information, when it is opened on excel. Therefore, if you are facing issues to import it, check if it has a similar format as the Marvin_Strategy_Optimization.csv disclosed in the installation process.
*Some Mining Packages export data with letters and values between quotation marks(“”), check if this kind of format is interfering in the importation process. **If you need to join columns a useful tip used in Excel is the formula: =A1&”,”&B1&”,”&C1 ….