The hold function is available immediately after switching on. So:
1. press the on/off button
2. the scale needs approx. 2-3 sec until it is ready for the first measurement.
3. you can immediately place an empty container (as a "tare") on it and briefly (~ 1 sec) press the "Hold" button.

==> At this moment the display switches to 0 (zero) so that you can weigh the contents that you then put into the container.

If your scale takes more than 10 seconds to do this, I think there could be one of the following problems:
1. the scale is not standing on a straight + stable surface (==> choose a better location)
2. battery is empty (==> replace battery)
3. technical defect of the scale (==> notify customer service if necessary)

Good luck!