Tra từ firstly - Từ điển Oxford Advanced Learner 8th

first·ly [firstly] BrE [ˈfɜːstli] NAmE [ˈfɜːrstli] adverb
used to introduce the first of a list of points you want to make in a speech or piece of writing
•There are two reasons for this decision: firstly…

Language Bank:
first
Ordering your points
▪ This study has the following ▪ aims: first ▪, to investigate how international students in the UK use humour; second ▪, to examine how jokes can help to establish social relationships; and, third ▪, to explore the role that humour plays in helping overseas students adjust to life in the UK.
Let us begin by ▪ identifying some of the popular joke genres in the UK.
Next, let us turn to ▪ / Next, let us consider ▪ the question of gender differences in the use of humour.
Finally ▪ / Lastly ▪, let us briefly examine the role of humour in defining a nation's culture.
notes at ↑firstly, ↑lastly
Language Banks at ↑conclusion, ↑process

Which Word?:
firstly / first of all / at first
Firstly and first (of all) are used to introduce a series of facts, reasons, opinions, etc: ▪ The brochure is divided into two sections, dealing firstly with basic courses and secondly with advanced ones. Firstly is more common in BrE than in NAmE.
At first is used to talk about the situation at the beginning of a period of time, especially when you are comparing it with a different situation at a later period: ▪ Maggie had seen him nearly every day at first. Now she saw him much less.