So my advice is: Right now tension belts using https://belt.connect.prusa3d.com (can be used from phone) Donť use the firmware app due to harmonic frequencies of the belt (the belt looks like it's properly tensioned, but it's not)
After that you can confirm you tension using firmware app.
Second advice: before first print don't forgot to lube Z screws. You will avoid horrible sounds from bed move. (https://help.prusa3d.com/article/regular-printer-maintenance-core-one_829710)
I would suggest skipping ahead to step 5. Turning on the printer, do step 6, step 7 (connect to your WiFi, add your printer to the Prusa app), and at step 8. Wizard: Intro select cancel. Then scroll to the LCD Menu > Settings > Manual Belt Tuning and follow the on-screen instructions. This will run the Belt Tuning Wizard which uses stroboscopic feedback to very accurately read the upper and lower belt resonant frequencies (accurate to 0.5 Hz) and recommend exact adjustments to the belt tensioner screws. This was much easier than all the other options. See https://help.prusa3d.com/article/adjusting-belt-tension-core-one-l-core-one_845048 for detailed info.
When you are finished adjusting the belt tensioner screws, you can return to Step 9 in this guide and complete the rest of the self-tests and calibrations. On the LCD Menu navigate to Control > Calibrations & Tests and select 1 Fan Test. I found that after this test completed, the printer software asked if I wanted to continue the calibrations and tests, and it proceeded through the rest of the tests in sequence automatically.
This is confusing. The procedure described in 'Adjusting belt tension (CORE One)' assumes that the printer is powered up, but if you'll power it up, it will guide you through the entire calibration process from the start without allowing you to go to menu and run tensioning process. I assume that should be tuned by acoustic natural frequency using the app here.
This should state that the belts need to be a bit tight, since they should be quite loose at this point in the process. Tighten them just a bit so there is no slack before moving to the tension process. This step should also note that the app should be used since there is no power to the printer yet.
So my advice is:
Right now tension belts using https://belt.connect.prusa3d.com (can be used from phone)
Donť use the firmware app due to harmonic frequencies of the belt (the belt looks like it's properly tensioned, but it's not)
After that you can confirm you tension using firmware app.
Second advice: before first print don't forgot to lube Z screws. You will avoid horrible sounds from bed move. (https://help.prusa3d.com/article/regular-printer-maintenance-core-one_829710)
When you are finished adjusting the belt tensioner screws, you can return to Step 9 in this guide and complete the rest of the self-tests and calibrations. On the LCD Menu navigate to Control > Calibrations & Tests and select 1 Fan Test. I found that after this test completed, the printer software asked if I wanted to continue the calibrations and tests, and it proceeded through the rest of the tests in sequence automatically.
I assume that should be tuned by acoustic natural frequency using the app here.
Tighten them just a bit so there is no slack before moving to the tension process.
This step should also note that the app should be used since there is no power to the printer yet.