The title says it all.
!create (element name here) (coordinate X) (coordinate Y) :)
I mean my own elements (like obsidian, gold, etc.)
I don't think you can create elements from scratch using console, you have to learn C++. You can, however, modify current elements using TPT.EL commands.
I thought there was a tpt.el.bran.name="gold"
Use elem.allocate. If using a LUA script with multiple lines (including ones run using the Script Paste mod), you can also store the resulting element ID in a variable to make it easier.
Example:
local bees = elem.allocate("MODNAME", "BEES")
(creates a new element stored in local variable "bees" and global variable "elem.MODNAME_PT_BEES")
From there, you can assign properties such as the name, color, transitions and functions (more info here).
Example (continuing from MODNAME_PT_BEES):
elem.element(bees, elem.element(elem.DEFAULT_PT_DESL))
elem.property(bees, "Name", "BEES")
elem.property(bees, "Color", 0xFEFE0E)
elem.property(bees, "MenuSection", elem.SC_NUCLEAR)
(takes our previously made "BEES" element, makes it into a copy of DESL, and changes the color (to yellow), name (to BEES) and section (to Radioactive))