Hi Ruby, here's how I did it, and it lasted 10 years
Lightly sand to rough the countertop up
Go to your paint store, tell them what you are painting, they will pick the proper paint and primer for you, you can even get the primer tinted for a better coverage
Once you have sanded, clean with TSP, then rinse and dry thoroughly,
Apply your primer coat, let it dry according to the instructions
Once the primer coat is dry, apply your paint coat, I would apply 2 or 3 as it will be stronger and thicker
Once your coats dry, you can apply a matte clear coat, either by spry or roll on, keep a small container of it under your sink for touch ups, I had my counters like this for 12 years, until I could afford new ones.
I used a few uncolored glass cutting boards for protection. It held up very well. And only costs you the prices of the materials.
Hello. Here is a hometalk link for diy countertop painting.
Additionally - Here is an idea that I find exciting and interesting for your consideration. I hope this helps.
Here is a helpful article: https://www.hgtv.com/remodel/kitchen-remodel/painting-kitchen-countertops