Syncthing

I want to install and try Syncthing on my own computer.

Official repository: https://github.com/syncthing/syncthing
Official site: https://syncthing.net
License: MPL-2.0

Before you do anything:
1. Read the README and install notes in the official repository above, and nothing else. Do not follow third-party tutorials or mirrors.
2. Tell me in plain words what will be installed, what it needs (operating system, memory, graphics card, disk space, accounts) and what it will cost me, if anything.
3. Check my computer against those needs and tell me honestly if it will not work well.

Install it as a regular desktop app: download the latest release for my operating system from the official releases page or the official site, install it, and open it with me.

Rules:
- Show me each command before you run it, and say what it does.
- Ask before anything that deletes files, changes system settings, opens a network port or needs an administrator password.
- Never put my passwords or keys on a command line, or in a file I did not choose.
- When it is installed, help me check it with one small test, and tell me how to start and stop it.
- If something goes wrong, explain it in plain words and do not guess your way around it.

Good to know before you start: There is no cloud copy, so at least one device must be on for syncing to happen. It also is not a backup. Deleting a file deletes it everywhere.