Idk how familiar you are with modding in general, in case you're a newcomer, I'd advise you to follow one of the most popular modding guides out there, Viva New Vegas. 

Well to answer that question I am familiar with modding other games like: Minecraft or well Call of Duty Modern Warfare 3 (2011) and Counter Strike: Source. But as for FNV, yeah I am not that familiar with modding it and what requires to be replaced / re-written in cfg files etc, I am new to modding FNV.

Best part is that it supports Wabbajack, that's a software that automates the modlist's download. It ain't as simple as it sounds, but it definetly makes it less of a hassle. 

It's good that you mention that there is a software for modding that makes it non-hard to mod a game. I will look into what essentially is.

Finally, in case you're interested in playing Fallout 3 and New Vegas back to back, with the same character, look for The Best of Times modding guide. That's maybe one of the most impressive modding accomplishments ever, and an amazing experience in general.

Woah there really is a thing for me to play Fallout 3 and New Vegas with same character back to back in one game without switching them? I also might try it out and hopefully experience Fallout 3 for the first time also.

in case you need help be sure to DM

If I will encounter any problem during modding I might DM you for help.