is it after the stage 4 Apptitude test, that the employer will employ staff?

It depends on the organization and the position you are applying for. In banks for instance putting on suit is recommended. Applying for engineering position, suit isn't necessary. Having a pretty knowledge of what an organization loo out for help one to know the dress code for interviews.

please can i know the grade, the employers are looking for HND Holders.

Its depend bro,its depend on organization,but my advice for u is to always dress coperate when going for the interview

My response to this question would be a yes. When going for an interview, you are expected to dress corporately and look smart. However, the most recognized corporate wear is a dark coloured suit well, for most job interviews. People try to play around this, works for some and doesn't for other. Just to be sure you're safe, put on a suit.

It is just ideal but not a must. All the best in your endeavors. God Bless

not necessarily, dressing co-operately does not necessarily include wearing suit.
a nice shirt, tucked in plain trousers, with or with out a tie, can do nicely.

Simply put, you need to be dressed to type. Today, there are Skype, Phone, Online, Paper

Its depend on d JOB you are going for like BANK

Suit makes u responsible,,,,,,...........

No buh suit makes u more presentable dan buh can wear chinOs buh no tight on skin dat it will show all ur bOdy if u can look smart no other attire it cute