From a later posting you made (now closed), you said you are using a HG521.
See the first two links below for best guesses at your router's interface. Your router has a very configurable QoS policy. Try the Help buttons at the right of each tab for any additional clues. Unfortunately, the interface appears to use the standard industry terms found in enterprise routers supporting QoS. This means you need an industry knowledge of QoS.
Before you start, backup (printed or electronic) your current router settings and practice a hardware reset of your router to factory default and restoring or rebuilding the settings. In the worst case that your QoS work appears to make your router perform poorly or be unusable, it may be easier to reset the router to defaults and restore your original settings.
You have two parts to deal with, and they are not easy nor intuitive -- modifying classifications to match your source machines and place the traffic into a queue, and assigning bandwidth to each queue. I added two video links below. The first covers QoS in general, and the second describes QoS on Cisco enterprise routers and helps explain some of the acronyms in your Huawei interface, and why the number of queues may not be the same on all devices.
For your basic requirement, go to Advanced -->QOS -->QOS, and select the Classification tab. create a classification rule that matches the MAC address of your computer (or IP address if your PC has a fixed IP address). In the Operation portion, set DSCP of 63 and assign to Queue 1; I believe this will put the packets in queue 1 of your Priority Queue. Attempt to create a second classification rule to match everything else: try leaving everything blank, and in the operation portion assign to Queue 4. I believe this will put everything else in queue 4 of one of the classified queues, which should be below your priority queue.
Back in Advanced-->QOS-->QOS, select the QoS tab, then in the first QoS sub-tab, allocate approximately 70% of your upstream bandwidth to your Priority Queue, and 20% of whatever other queue(s) are listed there (I don't know what other queues you have listed in that first sub-tab). From various searches and links on your previous iteration of this question, you should start by allocating bandwidth a bit less than your usual upstream bandwidth, then adjust upward until odd things start happening with your highest-priority queue. I found a few links that described how the QoS features on some home routers throttled connections significantly more than the actual available bandwidth, requiring users to experiment with levels above the actual upstream bandwidth to get optimal results.
I believe you can ignore the policer sections for now. The policers enforce minimum and maximum traffic levels for classified traffic
Keep track of your work, because I could not find any documents showing how to configure QoS on a Huawei EchoLife router.