Duduklah dengan santai di kursi Anda. Letakkan tuba di pangkuan Anda. Gunakan posisi tangan yang benar. Rilekskan bahu Anda.

Given the above summary, write a detailed text in English for it.
Your back should be straight, and your head should be lifted comfortably so that you're looking straight ahead at the conductor, if there is one, or straight ahead if you're playing alone. Your back should not be touching the back of the chair, your feet flat on the floor. Depending on your height, it may be appropriate to rest the tuba on the chair between your legs or rest it on your lap, gently on the top of your thighs. If it's a full-size tuba, you may want to get a stand to set it on. It's important to position the tuba in such a way that you will not have to bend yourself to reach the mouthpiece. Bring the horn to you, don't bend to the horn. When you try to fill the horn with air, you'll notice a big difference. On a right-handed tuba, you'll lean the tuba slightly to the left, using your left hand to support the lean. Place your right hand on the valves, either on the broad part of the pad on a rotary tuba, or with your fingertips on the center of the valves on a valve tuba.  Most tubas have a small ring to put your thumb through. This forces your hand to stay in place and helps give a bit of support from your right hand. Find the ring, if your tuba has one, and position your hand accordingly. On a lefty tuba, you'll be resting the tuba practically on your left leg which is why stands are very important for lefty players. Your right hand has to reach for the valves, but it will also be providing a lot of support. The left hand will keep things balanced. Although it may be tempting, do not curl your right thumb. That causes your fingers to be under your valves with only the tips on top.  Hold your fingers upwards on top of the valves so that they go straight up and straight down when pressed. Let your lap support the tuba, not your arms. Try to relax your shoulders and let your arms hold the tuba loosely. Treat it like your date, not like your wrestling partner. The more comfortably you can move around the horn, the better you'll be able to play.