Wash the fresh cranberries and add it to the instant pot.
Add the sugar and mix well with the cranberries.
Also add the lemon juice and 2 cups of water, mix well to combine.
Close the instant pot with lid in sealing position and cook in high pressure for 5 minutes.
Do a natural pressure release. If you are in a hurry, you may carefully do a gradual manual pressure release after about 15 minutes of natural pressure release.
Once the pressure is all released, carefully open the lid.
Stir the contents very well (you may gently mash with a ladle or spoon if needed, but do not mash a lot as it will make the filtering of the juice difficult).
At this point, you may taste (the contents will be hot, so do carefully) and see if the sweetness is enough. If needed, add little more sugar, stir well to mix with the cooked cranberries so the added sugar will dissolve well with the contents in the instant pot.
Let this cooked mixture sit for a while so it will cool down completely.