You can load a generic tab or comma delimited text file by clicking the open table icon on the AIJ toolbar (
) and selecting the file. For a comma separated file, name it .csv. Try .txt for a tab delimited
file. You can include a header row with labels. Otherwise they will show up as generic labels and you will have to figure out which labels correspond to which data columns.
If your input data are in magnitude, you will need to select "Input in Mag" on the corresponding plot row of the Multiplot Y-data panel.
You will always have more flexibility with an AIJ produced photometry table, so if you have access to the images, it would be well worth the effort to re-run the photometry in AIJ.