You don't have to pass journal entries in Tally for entering opening balances. You will have to create new ledgers and at the time of creating new ledger you can input opening balance.
To create a new ledger follow these steps :
Masters > Accounts Info > Ledgers > Create > Ledger Name > Under 'Select Category' > Enter Opening Balance
To enter stock in Tally there are two methods :
Integrated Accounts (Default Method) :
Step 1 : Create the unit of measurement from - Masters > Inventory Info. > Units of Measure > Create > Enter Symbol > Enter Formal Name
Step 2 : Create Inventory Item from - Masters > Inventory Info. > Stock Items > Create > Enter Name > Select Unit > Select Costing Method (FIFO Perpetual is advised here) > Enter Qty, Rate & Value
Non Integrated Accounts (Manual Stock Method)
Step 1 : Press F11 > Accounting Features > Set Integrate Accounts with Inventory to 'No'
Step 2 : Go to Masters > Accounts Info. > Ledgers > Create > Enter Name of Stock Item > Under 'Stock-in-Hand' > Enter Opening Balance