No problem, it's a series I've been with from the beginning and I have a passionate knowledge of that I love to share haha.
Also, here's a tip as you go along: stop watching .hack//SIGN after episode 26. Episode 27 is just a recap, and episode 28 takes place after the 4th game. 28 wasn't aired on tv as it contains spoilers as to the ending of the game's and should just be watched after.
As you go through watching the games, it's also good to know that there was an OVA packed with each game called .hack//Liminality. Episode 1 of Liminality should be watched after the first game, 2 after the second, etc.
Once you make it through all of that, the next anime is .hack//Legend of the Twilight. Its pretty lackluster and unnecessary though. Fun to watch some shenanigans a couple years after the previous series' if you want, but that's about it.
As for //Roots, it has a similar thing as //SIGN. When it aired on tv, they stopped airing new episode after episode 21 instead of 26. This is honestly a good place to stop for now because those last 5 episodes reveal a couple plot points that could be considered spoilers for the first and second G.U. game, so watch 22-26 at your own discretion.
There's a long-winded explanation you didn't ask for on how to watch this series, I hope you enjoy!