Use WinRAR or 7-Zip . These tools are specifically designed to recognize the "split" and will automatically combine them.
Filenames like "S2ckb0yDODI2GB" are often randomized or obfuscated to prevent automated copyright flagging. Common types of content found in these naming schemes include: Highly compressed installers for PC games. S2ckb0yDODI2GB.part03.rar
You will usually see files ending in .part01.rar , .part02.rar , .part03.rar , and so on. Use WinRAR or 7-Zip