I put this in the other knife thread.
You need a hand sharpener - example - https://tinyurl.com/y9veh4lx Amazon/Walmart/Kitchen Supply. Other posters will suggest a whetstone or sharpening stone(s) but for your light usage, one of these is fine.
Also get a sharpening steel (note: doesn’t actually sharpen, just hones/straightens the fine tip of the blade between uses). - example - https://tinyurl.com/y7kxlqnv - Amazon/Walmart/Kitchen supply store.
Use the sharpener to get the blade back in shape, coarse groove then fine groove. Sharpeners come with instructions. I do it every couple of weeks and I use Mercer knives daily. Use the hone after every cutting episode. Wash the blade as usual (by hand), run the steel over it (see youtube videos), wipe and put away. The wash/hone/wipe takes less than 30 seconds while the food is cooking. I can shave hairs off my arm with my knives - not recommended while cutting food 