Hi Beny,
After installation , you have to integrate your ERP system with solution manager. In solution manager system you have to configure managed system. Then you have to generate Support stack. xml file using MOPZ (Maintenance optimizer ). MOPZ will calculate target support pack level and download required all support pack files and keep in download manager from there you can download all files.
Don't download all individual patches. Everything will (required patches) will take MOPZ.
Thanks
Siva