4週6日目 使用にあたって
Perspective・object・obligation
接続：N／V辞書＋にあたって
important occasion, at the beginning
注意 / Note：The three samples in the same article all say "on occasion", differing in their POSITION relative to the event. 〜にあたって is right at the beginning, 〜に際して is right at that moment, 〜に先立って is BEFORE it happens. All three are only used for important occasions, not for daily chores.
比較 / Compare：Same article: 〜に際して／〜に先立って. These models are often mistakenly chosen for each other — carefully read the 接続 and nuances above and then decide.
よく出る形 / Common form：名詞・動辞書形＋にあたって／にあたり。Or go with 開会・入学・出発・新年. The latter is usually a greeting or preparation.
開会にあたって、一言ご挨拶します。
On the occasion of the opening, I would like to say a few words.
留学するにあたって、準備を始めた。
When preparing to study abroad, I started making arrangements.
新事業を始めるにあたって、多くの方のお力を借りた。
When I started my new business, I relied on the strength of many people.