Open palette automatically on startup

I have a custom palette that I use constantly (code below). I would like it to open automatically when I first open Mathematica (13.0.1.0 for MacOS). Is this possible, and if so, how?

I did look at the answer here about init.m files, but TBH I found the discussion a bit baffling - especially since there is zero 'how to' documentation in the help, just a description of what an init.m file is (nothing on methodology). It's also slightly unnerving since one user reported that his original init.m file got wiped.

In short, I need more hand-holding than you might expect! I'd be really grateful for help.

The palette code:

styleButtons = (Button[Style[#1, 14, FontFamily -> "Calibri"], FrontEndTokenExecute[InputNotebook[], "Style", #1], Appearance -> "Palette", ImageSize -> 250] & ) /@ {"", "Item", "ItemNumbered", "ItemParagraph", "", "Subitem", "SubitemNumbered", "SubitemParagraph", "", "DisplayFormula", "DisplayFormulaNumbered", ""}; gapButton = Button[Style["", 14, FontFamily -> "Calibri"], "", Appearance -> "Palette"]; align = Button[Style["Align", 14, FontFamily -> "Calibri"], NotebookWrite[InputNotebook[], "\[AlignmentMarker]"]; SelectionMove[InputNotebook[], All, Cell]; SetOptions[NotebookSelection[ InputNotebook[]], TextAlignment -> AlignmentMarker], Appearance -> "Palette"]; turnOffAlignment = Button[Style["Un-Align", 14, FontFamily -> "Calibri"], SelectionMove[InputNotebook[], All, Cell]; SetOptions[NotebookSelection[InputNotebook[]], TextAlignment -> Inherited], Appearance -> "Palette"]; copyCellRef = Button[Style["Copy Reference", 14, FontFamily -> "Calibri"], Module[{cell, tags, tag, createTag}, cell = First[Cells[NotebookSelection[ InputNotebook[]], CellStyle -> "DisplayFormulaNumbered"], MessageDialog["Select an equation cell!"]; Return[]]; tags = Replace[CurrentValue[ cell, CellTags], t:Except[_List] :> {t}]; createTag := With[{newTag = CreateUUID[ "eqnID-"]}, SetOptions[cell, CellTags -> Append[Select[tags, Not @* StringMatchQ["eqnID-*"]], newTag]]; newTag]; tag = SelectFirst[tags, StringMatchQ[ "eqnID-*"], createTag]; If[Length[Cells[InputNotebook[], CellTags -> tag]] > 1, MessageDialog["Multiple cells with same tag \ found!\n Tag of current cell will be \ regenerated."]; tag = createTag]; With[{tag = tag}, CopyToClipboard[Button[ Row[{"(", Dynamic[CurrentValue[ First[Cells[CellTags -> tag], $Failed], {"CounterValue", "DisplayFormulaNumbered"}]], ")"}], Appearance -> None]]]], Appearance -> "Palette"]; pasteCellRef = Button[Style["Paste Reference", 14, FontFamily -> "Calibri"], Paste[], Appearance -> "Palette"]; CreatePalette[Column[Join[styleButtons, {align, turnOffAlignment, gapButton, copyCellRef, pasteCellRef, gapButton}], Spacings -> 0, Alignment -> Center], Saveable -> False, WindowTitle -> "Cell Styles & Cell Ref"];