I have 2 questions that I need to ask:
1. The there is a Bill given to us on October 3rd for bicycle parts at $1150 that are delivered in the time from April 1st to September 30 for our bicycle repair service; the fiscal period ends March 31st. My question is it correct to account these as merchandise or supplies? And do we account both entries on the single day as:
(ps there is no actual number of parts sold or used, it just says parts delivered... But we must assume that they are used in order to help generate profit from services in the other transactions)

Db bicycle parts 1150
Cr cash 1150
Db bicycle parts expense 1150
Cr bicycle parts 1150

Or is it:

Dr Inventory-parts
Cr cash
Dr cogs
Cr inventory-parts

2. On the bank statement of account there is a bank annual service charge of 600 deducting from my bank account as the last transaction; is it correct to do:

Cr bank expense 600
Db cash 600

You need to get a clear idea of your bank account. A balance in your bank account is an asset; a debit, so anything that reduces it is a credit. Similarly an expense is a debit, an asset expended

When you acquire an asset; parts used in your business you would debit the parts inventory, then on balance date you would take inventory of the parts and transfer the value of those used to Cost of Goods Sold