A good jigsaw…
With a clamped straight edge… it makes great straight cuts.
Free handed… it can make curves and radius cuts.
And if it has an angle adjustment… It can make bevel cuts and angles.
As for joinery give Pocket joints a try. They’re quick, cheap and strong. I use them to start all of my prototypes.
But PLEASE, be very careful and read and learn about the tools before using them. Good Luck.