in page https://www.zabbix.com/documentation/3.0/manual/config/items/itemtypes/snmp
Have this text:

Enter the SNMP 'Port' as 161 and the 'Key' as something meaningful, e.g. SNMP-InOctets-Bps. Choose a custom multiplier if you want one and enter an 'Update interval' and 'History storage period' if you want them to be different from the default. Set the 'Type of information' to Numeric (float) and the 'Store value' to Delta (important, otherwise you will get cumulative values from the SNMP device instead of the latest change).

The problem is: Dont have a "Delta" option... have only "Delta (speed per second)" or "Delta (simple change)".

In image bellow show as selected the first option, so, I think the correctly text can be:

Enter the SNMP 'Port' as 161 and the 'Key' as something meaningful, e.g. SNMP-InOctets-Bps. Choose a custom multiplier if you want one and enter an 'Update interval' and 'History storage period' if you want them to be different from the default. Set the 'Type of information' to Numeric (float) and the 'Store value' to "Delta (speed per second)" (important, otherwise you will get cumulative values from the SNMP device instead of the latest change).