Hi @miamccull,
Welcome to the Bunnings Workshop community, it is wonderful to have you with us.
It would be worthwhile for you to have a quick read through How To Restore Furniture and How To Restore A Timber Table In A Few Easy Steps, as the process is much the same: sand it back to remove the current coating, repair any cracks or damage, then apply your new coating.
Ideally, you would remove the benchtop for this process; however, this isn't 100% necessary. If you didn't, it would mean you need to be more cautious around the edges and use painter's tape to mask off the surrounds and protect them. If you removed the benchtop, sanding it and staining it would be much easier, but it would also mean reinstalling it afterwards and reapplying the silicone around it. There are pros and cons to each, and I will leave the choice up to you.
Regardless of what you choose, the process would involve sanding it, cleaning it down, then staining and sealing.
It can be hand-sanded; however, it will be a lot of work, so if you don't already have one, investing in a random orbital sander would definitely be worthwhile. Start with 80-grit sandpaper for the initial sanding to remove the existing coating. Once the coating has been removed, wipe the surface down to remove sawdust, then use 120-grit, followed by 180-grit to get the surface nice and smooth prior to staining.
After this, ensure you get all of the sawdust off. This can be done with a brush, a damp cloth or a vacuum cleaner.
Once the surface is entirely clear of sawdust, I'd suggest you use a combination stain and varnish in a colour of your choosing. Apply your product using a high-quality brush or roller, ensuring you follow the instructions for application on the packaging.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
