Creating Analog instruction

Dear Friends ,
Iam new to RSLOGIX 5000 for creating ladder diagram using Analog Instruction.My problem is that i need basic steps to develop analog instruction ,Where i could find this instruction like as an options , How could i develop this instruction . I need just a basic idea to create this instruction in ladder .
Thanks

Depends on what you want to do, but most of the time an analog value is going to be used with the Compare and Math instructions.