What kind of playstyle do you want? Melee, caster, or ranged?
There are no beginner guides for witch hunter in this forum yet (one of the few classes that still has no beginner guides), but it should be possible to do a decent budget acid melee, caster, or ranged char with it.
However, there is a Sentinel acid caster from Nery here: [1.1.2.5] [caster] Beginner's/budget acid Sentinel. You could either choose Sentinel instead of Witch Hunter or do a similar build with Witch Hunter (which should work fine too).
There is also an acid melee Dervish from Stupid_Dragon: [DW melee] Beginner's Virulent Dervish. You can’t do this exact build since you started as an occultist, but you should be able to do something similar with Witch Hunter (probably weaker though, since dervish is easier to build without gear). There are probably better gear choices if you choose to do something like this (acid melee DW) as a Witch Hunter though. If this is the case, I can try to help you with it.
There is some discussion about alternatives for a beginner Witch Hunter build in this thread: [DW melee] Beginner's Virulent Dervish. Most ideas revolve around using the ABB rifle (Ugdenbog Bilelauncher - Items - Grim Dawn Item Database), which is an MI made for acid 2h ranged ABB Witch Hunters. Ulvar1 posted a sketch of a similar build but done as a Dervish here: Dervish, Level 100 (GD 1.1.8.1) - Grim Dawn Build Calculator.
Let me know what playlist style and damage type you prefer, and I will try to help you further with it. There is some great endgame builds for Witch Hunter, but most of them require legendary sets (Venomblade, Rah’zin, and Dunefiend), which you won’t have access to as a beginner.