The eight-pin socket is used for programming EEPROMs from the 25xx series.
In order to write new firmware to older Harvesteman modules (but also Malgorithm Mk2 and Tyme Sefari Mk2), use the 2x5 pin header.
The six-pin connector with the fat white arrow is used to connect to a PicKit2 programmer.
A PicKit2 microchip programmer (PicKit3 works, too) is required for the Harvestman programmer. Get it at your electronics supply store.
The Harvestman Programmer is used as an interface between the PicKit2 and the module or the ROM chips.