The timer contains a counter that counts to some specific number (modulo) which determines the period.
The real time of the period is determined by the "time ticks number" * "length of the timer tick". The length of one timer tick is determined by input frequency of the timer set in the component.
For example, let's have 3MHz input clock and 10ms period (on-match mode using TPM0 modulo register for period is used because it allows adjusting the period).

Then, if you look into TU1.h (or other name if you renamed the component), you should have the constants like this:
...
#define TU1_CNT_INP_FREQ_U_0 0x002DC6C0UL /* Counter input frequency in Hz */
#define TU1_CNT_INP_FREQ_R_0 3000003.000003F /* Counter input frequency in Hz */
#define TU1_CNT_INP_FREQ_COUNT 0U /* Count of predefined counter input frequencies */
#define TU1_PERIOD_TICKS 0x7530UL /* Initialization value of period in 'counter ticks' */
#define TU1_NUMBER_OF_CHANNELS 0x00U /* Count of predefined channels */
So you can see that the period is 0x7530 ticks, which is 30000 in decimal base. The period in real time would be 30000 * (1/input frequency) = 30000 * (1/3000000) = 0.01s = 10ms
By the way, these constant are useful if you'd like to do time calculations in your code.
best regards
Petr Hradsky