How do I get into doing Fractals?
A lot of guilds do fractals and dungeons, you can join any party below level 10 as you will need agony resistance to go higher, aslong as it matchs your current level or higher you progress.
If you’re not already familiar with the instances I would recommend you skim over http://gw2dungeons.net/ for basic strats and assumed class responsibility.
Beyond that, to find a guild you can use the forum’s own LFG Sub Forum, or I also recommend Reddit’s Guild Recruitment page