Welcome to the forum!
BTW, your English is fine. 
A lot of people here - including me - aren’t English native speakers. Don’t worry. 
Since you got the Occultist mastery, you can always follow Mayas pet Occultis guide. Simply focus on the Occultist mastery and respec into the full “Will-o-Wisp” build later. At around level 70-75 or a bit later you can switch to the final build. That’s what I did, too, when I leveled this build.
Note that the real strength of the build lies in the “Reap Spirit” skill. So before you can transition to the final build, you need enough skill points to fill the Necromancer mastery bar AND put some points into “Reap spirit”. Before that you’re better off with strong Occultist pets - especially the Familiar is your friend.
Regarding gear: This build doesn’t include items that can be target farmed. Except for the weapon (the blueprint can be obtained from the “Cult of Bysmiel” faction in Forgotten Gods), everything you need are “random drops” you can find anywhere.
I’d suggest to level to 100. Then you can run rogue-like dungeons, Shattered Realm on Normal or maybe Elite difficulty or Crucible on lower difficulties (don’t try Gladiator with a fresh 100 character) to get better gear.