To get flyline connectivity, you will need to create nets and instTerms. Let's say you have a simple cell that consists of two instances I1 and I2. Each instance has a pin called IN and a pin called OUT. The OUT pin of instance I1 connects to the IN pin of I2 as a net named NET1. At this point, you have written the Skill code that creates the instances I1 and I2. You now need to create a net in the cell called NET1. You can then create instance terminals (instTerms) for I1 pin OUT and I2 pin IN that connect to NET1.
i1 = dbCreateInstByMasterName(cv "mylib" "myinv" "layout" "|I1" 0:0 "R0")
i2 = dbCreateInstByMasterName(cv "mylib" "myinv" "layout" "|I2" 10:0 "R0")
i1Out = dbFindTermByName(i1~>master "OUT")
i2In = dbFindTermByName(i2~>master "IN")
net1 = dbCreateNet(cv "NET1")
it1 = dbCreateInstTerm(net1 i1 i1Out)
it2 = dbCreateInstTerm(net1 i2 i2In)
I haven't run the above code but it should be close enough to working order. The instTerms describe how the nets connect to the instances so you can get flight lines. If you create top level pins using leCreatePin, it will create a net and a terminal and the pin shape all in the same command (without the need of using dbCreateNet, dbCreateTerm or dbCreatePin). You can find out more about these functions in the Cadence Design Framework II SKILL Functions Reference.