Fine 0000 wire wool. Meths to degrease.

Apply oil with fine 0000 wire wool for the first three coats, then apply with fingers if you so desire.

Oil containing tung oil will dry matt.
Linseed oil will dry gloss ( after enough coats)

Most oil preparations contain drying agents to allow the oil to dry quicker, over night as opposed to a week.

My personal choice is liberon finishing oil.

Apply the oil avoiding the checkering, remove as much as possible with a cloth and allow to dry.

When your happy give it one last coat including the checkering, toothbrush helps here.

I tried a walnut oil preparation. Compared to liberon finishing oil, it was not as good.