Both serial and IP networks use the same point attributes to locate values. The Slave id is the id with which the Modbus node was configured; it is a number between 1 and 240.
The Register range determines in which of the four ranges the value is to be found. Consult the documentation for your equipment to determine what should be used.
Coil status and Input status values are always Binary. However, Modbus vendors are often very creative in the ways that Holding and Input registers are used. The Modbus data type field reflects the many ways in which data can be encoded. Consult the documentation for your Modbus equipment to determine the proper setting.
Specific values are located with the Offset setting. This is a 0-indexed value, meaning that counting starts from 0. Some Modbus vendors provide documentation that is 1-indexed, where counting starts from one. As such, it is sometimes necessary to subtract one from documented index to determine the 0-indexed offset. When registers include their range, e.g. written as 0x30001, 1-indexing is typically implied. The Bit field is used when binary values are encoded into individual register bits.
The Multiplier and Additive fields can be used when trivial value conversions are required. Numeric values read from the network are calculated as follows: (raw value) * multiplier + additive. The reverse is applied when a numeric value is written to the network.