Running latexmk -pdf in this folder will generate main.pdf. Some useful development flags are latexmk -pv (preview) and latexmk -pvc (live preview).
latexmk -pvc -view=none -pdf -pdflatex="pdflatex -synctex=1 -interaction=nonstopmode" continuosly regenerates a PDF whenever the input file is changed, with SyncTeX enabled.