That will depend on how you set up your chart of accounts. Good advice is to spend a little for advice from an accountant now to keep you out of trouble later.
In general, however, assuming you deposit this working capital into a company bank account, just Receive Money in the bank account and allocate the transaction to an equity account. If you are setting up an owner’s capital account, allocate it there. But since you are a sole trader, everything the company owns belongs to you. A simple alternative is to rename
Retained earnings as
Owner's equity and allocate it there. Then there is no need to activate the
Capital Accounts tab.
First, you will have to activate
Inventory Items. Then, create all your items. You can read how to do this in the Guides. I assume the question you are really asking is how to handle this contribution of inventory purchased from personal funds. The answer is to use an expense claim, which is used to record company expenses paid from personal funds. You would otherwise handle this just like a purchase invoice, allocating to appropriate inventory accounts. The bigger question is what value to assign. Here, you will need to consult your accountant for local laws in order to understand whether you can value the stock at what you paid or must depreciate the value in some way. Essentially, though, an expense claim is like a contribution of capital. The transaction will create a liability in
Expense claims account, because the company owes you money. That liability must then be cleared in some fashion. You can either reimburse yourself by spending money from a bank account, or you can use a journal entry to transfer the claim to equity, debiting
Expense claims and crediting
Owner's equity. In a startup situation where the company is not yet flush with cash, the latter approach would be more usual.