"Step-by-step" can be Detailed. "Download" as before. "Obtain" becomes Acquire. "Working" in "working serial number" could be Working. "Serial number" is kept.
Next, "free trial version" – "free" becomes complimentary, "trial" as sample, "version" as copy. Each word is replaced with three options. Download Archicad 14 Serial Number
Next sentence: "Are you an architect, designer, or engineer looking to download and install Archicad 14,..." "Step-by-step" can be Detailed
System Requirements