The usual warning: I am not responsible if something goes wrong...
But it would be almost impossible for you to totally brick your phone by following this procedure.
1. Download the SuperSU zip file, for installing root through custom recovery: http://download.chainfire.eu/supersu (latest) or http://download.chainfire.eu/supersu-stable (stable) and copy it to the SD card in your phone (or download it directly with the phone). Do not extract any files from the zip file, you will use it as it is.
2. Download a custom Recovery like TWRP for Lenovo A2010: https://yadi.sk/d/0WaK6e4Mkx5cx
Extract the files from the archive to your PC. In fact you need only 2 files, "Recovery.img" and "MT6735M_Android_scatter.txt"
3. Windows: Install the MTK VCOM USB driver, if it's not already installed on your computer: https://yadi.sk/d/c4o7TaGLreNzx , extract the files from the archive to a folder in your PC, then install the driver.
You can also download and run this driver auto installer program, which will install more drivers, not only the MTK VCOM driver: https://cloud.mail.ru/public/31d13c2...v1.1236.00.zip
You may need to turn off driver signature verification though, as some of the drivers are not digitally signed.
Linux: see this thread http://forum.xda-developers.com/gene...linux-t3160802
4. Download the program SP Flash Tool from here: http://spflashtool.com/ and just extract the files from the archive. No installation is needed.
Depending on your Windows language, you might want to make sure there's no non-Latin characters in the path. If that is your case, a short path like C:\flashtool is the best choice.
5. Run SP Flash Tool to install the custom Recovery.
You should also note that the phone has to be turned off, with or without battery, and at 0:35 in the video, when he clicks "Download", he then connects the phone to the computer.
6. Reboot to Recovery by holding the Volume Up button pressed while the phone is booting.
In the boot menu that appears, move the selection cursor to the [Recovery Mode] option, by using the Volume Up button, then press the Volume Down button to select that option.
You should now get into TWRP Recovery, that you flashed in step 5.
7. From TWRP Recovery, install the previously downloaded file (UPDATE-SuperSU-v2.xx.zip).
8. Reboot. Your phone is now rooted.
Method #2 (no PC needed):
The latest version of KingRoot seems to be working on Lenovo A2010.
After rooting you can install TWRP through rashr.
But if you have a PC and can install SP Flash Tool, I would still recommend the first method above.