If you have not installed Diablo II Resurrected yet, depending on how you bought it you can first visit the Battlenet Game Installation Guide OR Steam Game Installation Guide
Click here to learn the differences between the Battle.net & Steam versions of the game Diablo II Resurrected.
Reimagined Launcher (Very Easy) Installs in Windows & automatically updates itself, available on Nexus Mods OR the Main Website HERE. With one-click it can find the latest version of Reimagined online too. Auto backup for your saved games.
Manually follow-the-steps (Easy/Hard): You will lookup your own installation directory & you'll be responsible for backing up your own saved games incase a crash occurs during a loading screen.
C: Drive is the most common install location. Yours may differ depending on your setup. Launcher finds them automatically.
Battle.net D2R Mod Files:
C:\Program Files (x86)\Diablo II Resurrected\mods\ReimaginedSteam D2R Mod Files:
C:\Program Files (x86)\Steam\steamapps\common\Diablo II Resurrected\mods\ReimaginedSaved Game Files:
*C:\Users\*%USERPROFILE%*\Saved Games\Diablo II Resurrected\mods\ReimaginedThree*
Highly recommend watching Ben's video. The installation process is very simple.
Video instructions HERE:
D2RLoader provides LAN TCP/IP support for Reimagined, including Reign of the Warlock (ROTW), without the former class and mechanic restrictions.
D2RLoader also allows for things like hundreds of shared stash tabs, among other settings that can be found here.
D2RLoader is still in active development, so installation steps and configuration options may change in future updates.
Before you begin: Everyone joining the same TCP/IP game must use matching D2R, D2RLoader, D2RLoader Plugins/Patches, and Reimagined compatibility-build versions, as well as any Reimagined Launcher Tweaks or Plugins/alterations to files.

Simply click the Mod + D2RLoader (or Ladder) box which will check if D2RLoader is installed.
If D2RLoader is not installed the launcher will download and install it for you

Once D2RLoader is installed it will say it has completed

As of writing this, the multiplayer button widget is not automatically added to the UI of the mod (future launcher versions will handle this step)
So hit the “Start Game” button to launch the game with D2RLoader enabled
Once the game has started click the red cog at the bottom

Then enable the multiplayer button

At which point you will now see a multiplayer button which will allow you to host and browse games

To host simply create a game with whatever the desired details and rules are

To join a game go to browse and then join any open games or join your friends games with their game ID and password

if hosting an unlisted/private game, then the host needs to provide the game ID from the party menu.

And viola you are now playing reimagined on the latest mod version with rotw content with friends

The most frequent change you will want to make is to have more stash tabs. To do so, while at the main menu, hit the red cog at the botton of the character select screen to open up the D2RLoader settings
Then go to gameplay tab and adjust the shared stash tab pages and materials limit (ROTW tabs for runes/gems/materials)

Once done check in game and see your max shared stash tabs have been increased

If you have issues with the D2RLoader or other installation instructions, visit the Reimagined discord for assistance. Comments on the wiki are ignored.
Here are some common resolutions to frequent crashing we've encountered in bug reports across the Discord, Nexus and Reddit.
1. Reimagined 3.0+ is not compatible with saves from Reimagined 1.x.x, Reimagined 2.x.x, D2R vanilla, or other mods if the save file contains items. Trying to place them in the saves folder and use them will often cause the game to crash.
2. Classic characters cannot be created and are incompatible with the mod.
3. Change graphics option VFX Lighting Quality off from Ultra to High or Medium as it barely has any visual impact but kills game performance and causes crashing.
4. Cap your framerate to your monitors refresh rate and/or use Vsync.
5. Don't Alt + Tab, (click out of the screen if playing in windowed) the game doesn't enjoy being out of focus. You can try to mitigate this crash by limiting the Background FPS of D2R.exe via your GPU Control Panel. (The game still likes to crash anyways but the background FPS limit helps reduce the frequency.)
6. Don't equip items on Mercs with Chance to Cast a minion. (Reanimate is fine, it is specifically CTC that seems to cause issues.)
7. Change Power Settings from Performance to Balanced (Unintuitive but seems to work for some people.)
8. If you are using other mods, you can try disabling them to see if the crashes continue but if they edit itemstatcost.txt then disabling them will cause crashes anyways so pay attention to what you are doing and make backups before experimenting.
9. If you are making local mod edits, undo those edits or reinstall the mod fresh.