Unfortunately, setting up is part of the deal of having a guitar. Well worth it to be able to help yourself, you can then experiment until the guitar feels good to you. You will need to invest in some simple tools. No need to go for the expensive luthier tools, you might have all you need already.
I recommend taking off material from the bottom of the (replacement?) nut and saddle with sandpaper. You can stick a piece on a flat plate of glass, on a piece of hardboard, your desk, etc.
You mark/measure what needs to come off (vernier calipers!), use coarse paper (waterpaper - start with 100 grit) to take off the most of it, and then finish up with, say 360 grit, and polish with 1000 grit. It is easy to hold things flat and square, you can work in a bit of an angle if required, thin down to fit the slots, and so on. It does take patience. As noted above, go in smaller steps, approach your target with a few runs of sanding, testing. Working on a flat surface guarantees a flat bottom for best piezo contact. As mentioned above, if you go too far, shim up again. If only a bit is required, paper shims work well, to get you back to where you should be, and paper shims are thin enough to allow you to "fine-tune". Once happy, you can find a hard shim of that thickness, or, just use thin superglue to harden the paper shims. After which they become sand-able, if you feel like removing a bit later on.
There is a lot of material on this forum, how-to's as well as "lookwhatI'vedone!" .
As I said, you must learn to do this. And, even though it is a bit of mess, I do recommend going with bone.