Feel free to get to level 12 and kill Brutus on your own. In fact I think it's a good idea as you'll actually gain some solo xp.
[If you are under leveled, just grind a little, and you should be good to go!]
Things to keep note of... Always do the Medicine Chest quest and get the Quick Silver Flask for faster movement. You don't have to turn in a quest every time you complete one, and you can complete quests that you've not started yet.
Remember to pickup scrolls of wisdom and portal scrolls and junk items, as well as sort/keep track of your inventory. (Sell the junk items for scraps [that turn into scrolls]/chromatics [that you'll need like a billion of eventually]).
Note: Do not pick up junk items after you kill Brutus, you should have quite a few saved up by then plus you'd be getting more just from regular pickups now.
For your early game gear, look for Blue item names, or Yellow item names, usually Yellow will be better so try to go for those. Look for stats like + HP, and % Damage... + Resistance is also nice but you shouldn't really worry about that until later. A good Yellow item can carry you for quite a while so you won't even have to think about sorting through loot/figuring out what to pick up.
After you kill Brutus get a warping movement skill gem (This will let you take shortcuts and get around faster). Flame Dash if you're Witch/Shadow/Templar/Scion, Blink Arrow if you're a Ranger, and Leap Slam if you're a Duelist/Marauder.
Ranger/Duelist can also take Whirling Blades but that will not let you take shortcuts like the skills I mentioned b4.
!!! IMPORTANT: Always use a Loot Filter the one I use is this one... https://github.com/NeverSinkDev/NeverSink-Filter/releases (Instructions: https://github.com/NeverSinkDev/NeverSink-Filter/blob/master/README.md )
PS: You can use Path of Buiilding ( https://github.com/PathOfBuildingCommunity/PathOfBuilding ) + Windowed Borderless to have an easier time following a guide.