It’s important to understand that when working with moving parts, the amount of force in which you tighten a screw or bolt is important. The parts you are attaching are designed by an engineer to stay together when tightened to a specific measurement, commonly referred to in the US as foot pounds of torque (ft-lb). These readings can also be performed in Newton meters (n-m) and kilograms per meters (kg-m). If you open a factory service manual (FSM) you will see an exploded diagram of various parts of an engine, and where the bolts are referenced you will typically see a small range of numbers. These numbers indicate the tolerance range that you should follow when tightening you bolt.
The easiest way to ensure a proper torque reading is with a torque wrench. There are a few different types, but I like the break-away style. They look like socket wrenches, but the handle will turn to set the preferred torque and then when you exceed that limit the head will click, indicating you have reached the limit and to stop tightening.
If you do not follow proper torque specifications, there is a good chance your engine, suspension, wheels, or other moving parts of your car can come apart causing serious damage or injury. So when working with an engine, don’t tighten it by feel or until you can’t turn it any more. Over-tightening can be just as bad as under-tightening. Follow the specs!
I am attaching a PDF showing some diagrams from the RB25DET head for your reference.