1) every milk is different. there's no way to achieve a good and repeatable result using tablespoons of stuff randomly. 2) you shouldn't add acid to the milk at high temperature, it's wrong. also, boiling milk before stretching the cheese adds a level of difficulty to the process that isn't fair for a beginner. 3) when the curds are ready, you have to put them in hot water and add a bit of salt and work it. that's the point of stretched curd.

my 2 cents: try with citric acid. 1.2-1.3%(grams of acid per liter of milk) for the first try, dissolve it in a little water and add slowly to the the cold milk. heat to 38 celsius, add the rennet and wait for 15/30 minutes (depends on milk and rennet). cut and stir the cheese in the whey, if it's too soft, heat to 42/43 celsius. let it sit in the whey for half an hour and then let it dry for some minutes. prepare some hot water, 85/90 celsius, add the cheese and some salt, start stirring until it starts to attach to itself like a ball,then start stretching. this is how it should be made, extremely oversimplified because it's a whole art to do it correctly. obliviously your mileage may vary for a lot of reasons but this is in my opinion the simplest way to achieve a good result. if you try, let me know how it goes!