How do I use this 2T thing? Where do I pour it?
The ratio is 1:200, that is 1 part 2T to 200 parts diesel, or 0.005 per ml or 5ml per liter.

If your tank capacity is 50 L, multiply it by 5 and that's 250 ml of 2T.

Before your next refill, take note of the pump price of diesel, let say its P50/liter, if you will buy P1000 diesel that is 20 liters, multiply it by 5 and you have 100 ml of 2T.

In an empty bottle put 100 ml of 2T, pour it to your diesel tank just before the gas boy fill it with diesel. 2T mixes well with diesel and does not come out of the solution.

Effects? only experince can tell you.

Risk? leaking injector seals.

What 2T to use? JASO FC like Castrol Activ or TC-W3 Marine 2T which is much expensive.