It is not clear for me if you have gone through the setup proces for accounting. There is a wizard available for this setup. Make sure you have set up with the right accounting charts for your country. This will help a lot. If your country chart is not available use the standard chart. You need also to setup year fiscal year and period.

If you have done this all then go to accounting/journal items. And use the journal "Opening Entries".

1. | Is creating an "Initial Capital" account, credit from it and debit into "Bank" account the right way? | - yes. Debit could be also another account (country and company specific), but the main thing that credit is "Initial Capital" (or "Share Capital").
2. | If YES, what is the "Internal type" shall the "Initial Capital" be categories? | - all accounts need Internal Type. For Initial Capital it's Regular.
3. | what is the "Account Type" shall it to be categories? Asset? Bank? Current Liabilities? | - all accounts need Account Type. Account Types are country specific, but if you are using UK account chart, then Account Type for Initial Capital could be Equity.

As Ton123 pointed out, you first need to define your chart of accounts. This is VERY country specific, so you better look for help from some accountant in your country if the chart is not available on OpenERP...

Once your chart is in place, you need to create what is called an "opening entry" that sums up the current state of your company at the moment you started using OpenERP: your capital, accounts payable and receivable, ...

Again, for that you better request advice from your accountant...

Initial setup is THE MOST important part using any ERP system, so you better do it right from the beginning, or you will suffer a lot latter...