You can subscribe to any of the execution algorithms brokers provide, Omnesys has something called I3 which is pricey…
A manual way of doing this could be to split your orders on a basket and send them manually at opening whilst controlling the quantities by monitoring the offer qty on your scrip.
By the way I suppose you actually mean a 'large quantity' of shares to transact in.
Bulk trade is a technical term used when you intend to transact in more than or equal to 0.5% of the total equity shares of the company outstanding in the market.
Watch out for the best 5 ask prices and quantity continuously and if a matching bulk order is available in the screen on the 5 best prices, place your buy order instantly to capture that.