Number of PRACH slots within a sub-frame in 5G NR

Hello Experts,
Can any one explain how the number of PRACH slots within a sub-frame value is obtained in 5G NR?
In 3GPP 38.211 v15.1.0-Table 6.3.3.2-2 <Random access configurations for FR1 and paired spectrum/supplementary uplink >, it is mentioned that the number of PRACH slots within a sub-frame is either 1,2 or ‘’-", depending on the preamble format.
Does the value “2” means that there are two slots available for one preamble transmission?
Or is it two slots for two different preamble transmission opportunities?