Only download from the official sites of these repackers. Avoid "mirror" sites that look suspicious, as they often contain malware. Antivirus:

While the idea of a 50GB game shrunk to 1GB is tempting, these files are almost always that carry significant trade-offs. ⚠️ The Reality of "Highly Compressed" Files

is a common way to save on data and storage, but it’s important to know exactly what you are getting into before you hit download. What to Expect from "Highly Compressed" Files

Go to the installed folder. Find SkyrimLauncher.exe or skse64_loader.exe (if the repack includes Skyrim Script Extender).

Downloading is the most efficient way to get back into the world of Tamriel. By choosing a repack, you save bandwidth and storage space while enjoying the full, uncompromised Dragonborn experience.