What does quiescent power mean and how I can find how much current the chip consume
Definition of Quiescent current from Maxim:

For an electronic circuit, a quiet state in which the circuit is
driving no load and its inputs are not cycling. Most commonly used for
the specification &quot;quiescent current,&quot; the current consumed by a
circuit when it in a quiescent state.

Definition of Quiescent current from TI

Unless otherwise noted in the datasheet for a part, \$I_Q\$ is defined as
the current drawn by the IC in a no-load and non switching but enabled
condition. “No load” means that  no current leaves the IC to the
output.

from Xilinx:

Quiescent power (also called static power) is the power drawn by the
device when it is powered up, configured with user logic and there is
no switching activity

from NXP for an LDO:

Quiescent or ground current, is the difference between input and
output current. It  describes the current which the LDO consumes by
itself. A low quiescent current  \$I_Q\$ improves the current
efficiency of an LDO



how I know how much the chip consumes

In your application, as per data sheet, the quiescent power is about \$3.6 uW\$  which can be derived from operating voltage and maximum supply current required for operation.

Below table also gives information about typical current draw in graphs which can be considered as reliable average data for calculations: