I am not trying to discourage you, but I have been in the Printing and Graphic Arts fields for 29 years and have had my own sign & graphics business for 10 years. You will need guidance and consultants can get expensive. I know as I routinely consult with small printing companies and graphics businesses and bill at $125 per hour.
With that said, here are a few things you will need:
Vinyl Plotter - minimum of 30” for cut vinyl graphics
Computer and Plotter software such as Flexi or Sign Lab
Large Format Printer. Minimum 30” preferably 54 or64 inch. This can be as stand alone printer such as a HP latex machine, Epson Solvent machine or a combination print cut machine like a Roland VG2 machine.
If you opt for the printer only option, your plotter cutter will need to be big enough to mate with the printer.
Laminator. You will need at minimum a good large format cold lamiator such as a Royal Soverign 55” (depending again on size of your printer)
Rip Software for your printer/cutter. Many printers need their own specific rip software. Some such as Roland come with sale as bundle.
Layout Table. A minimum 4x8 layout table will be required for masking, weeding and preparation
Masking Station. I use a second Royal Soverign laminator in 36”, but you can get away with cheap options such as Masking machine.
Board Cutter. I have several keencut table top cutters an A-frame board cutter and a panel saw, but you can get away with some hand tools and guides to start.
Computer with graphics software. I am all about top end Mac’s here. I have a MacPro with128gb ram. (The more the better) and I have Adobe Creative Suite for file preparation.
To truly be effective, you will also need to set your shop up with good lighting preferably LED with 5000K temperature to make sure your color looks good, or you will be reprinting jobs over and over.
Vendor relationships are key. You need to set up vendors for product and backups as well, so you can always have good materials and advise.
Next and finally you will need a customer base... This takes time and experience.
Good Luck.